with whom Justice Brennan and Justice Stevens join, dissenting.
In each of these consolidated cases, police officers, ignoring clearly visible “No Trespassing” signs, entered upon private land in search of evidence of a crime. At a spot that could *185not be seen from any vantage point accessible to the public, the police discovered contraband, which was subsequently used to incriminate the owner of the land. In neither case did the police have a warrant authorizing their activities.
The Court holds that police conduct of this sort does not constitute an “unreasonable search” within the meaning of the Fourth Amendment. The Court reaches that startling conclusion by two independent analytical routes. First, the Court argues that, because the Fourth Amendment by its terms renders people secure in their “persons, houses, papers, and effects,” it is inapplicable to trespasses upon land not lying within the curtilage of a dwelling. Ante, at 176-177. Second, the Court contends that “an individual may not legitimately demand privacy for activities conducted out of doors in fields, except in the area immediately surrounding the home.” Ante, at 178. Because I cannot agree with either of these propositions, I dissent.
HH
The first ground on which the Court rests its decision is that the Fourth Amendment “indicates with some precision the places and things encompassed by its protections,” and that real property is not included in the list of protected spaces and possessions. Ante, at 176. This line of argument has several flaws. Most obviously, it is inconsistent with the results of many of our previous decisions, none of which the Court purports to overrule. For example, neither a public telephone booth nor a conversation conducted therein can fairly be described as a person, house, paper, or effect;1 yet we have held that the Fourth Amendment forbids the police without a warrant to eavesdrop on such a conversation. Katz v. United States, 389 U. S. 347 (1967). Nor can it plau*186sibly be argued that an office or commercial establishment is covered by the plain language of the Amendment; yet we have held that such premises are entitled to constitutional protection if they are marked in a fashion that alerts the public to the fact that they are private. Marshall v. Barlow’s, Inc., 436 U. S. 307, 311 (1978); G. M. Leasing Corp. v. United States, 429 U. S. 338, 358-359 (1977).2
Indeed, the Court’s reading of the plain language of the Fourth Amendment is incapable of explaining even its own holding in this case. The Court rules that the curtilage, a zone of real property surrounding a dwelling, is entitled to constitutional protection. Ante, at 180. We are not told, however, whether the curtilage is a “house” or an “effect”— or why, if the curtilage can be incorporated into the list of things and spaces shielded by the Amendment, a field cannot.
The Court’s inability to reconcile its parsimonious reading of the phrase “persons, houses, papers, and effects” with our prior decisions or even its own holding is a symptom of a more fundamental infirmity in the Court’s reasoning. The Fourth Amendment, like the other central provisions of the Bill of Rights that loom large in our modern jurisprudence, was designed, not to prescribe with “precision” permissible and impermissible activities, but to identify a fundamental human liberty that should be shielded forever from government intrusion.3 We do not construe constitutional pro*187visions of this sort the way we do statutes, whose drafters can be expected to indicate with some comprehensiveness and exactitude the conduct they wish to forbid or control and to change those prescriptions when they become obsolete.4 Rather, we strive, when interpreting these seminal constitutional provisions, to effectuate their purposes — to lend them meanings that ensure that the liberties the Framers sought to protect are not undermined by the changing activities of government officials.5
The liberty shielded by the Fourth Amendment, as we have often acknowledged, is freedom “from unreasonable government intrusions into . . . legitimate expectations of privacy.” United States v. Chadwick, 433 U. S. 1, 7 (1977). That freedom would be incompletely protected if only government conduct that impinged upon a person, house, paper, or effect were subject to constitutional scrutiny. Accordingly, we have repudiated the proposition that the Fourth Amendment applies only to a limited set of locales or kinds of property. In Katz v. United States, we expressly rejected a proffered locational theory of the coverage of the Amendment, holding that it “protects people, not places.” 389 U. S., at 351. Since that time we have consistently adhered *188to the view that the applicability of the provision depends solely upon “whether the person invoking its protection can claim a ‘justifiable,’ a ‘reasonable,’ or a ‘legitimate expectation of privacy’ that has been invaded by government action.” Smith v. Maryland, 442 U. S. 735, 740 (1979).6 The Court’s contention that, because a field is not a house or effect, it is not covered by the Fourth Amendment is inconsistent with this line of cases and with the understanding of the nature of constitutional adjudication from which it derives.7
H-I HH
The second ground for the Court s decision is its contention that any interest a landowner might have in the privacy of his woods and fields is not one that “society is prepared to recognize as ‘reasonable.’” Ante, at 177 (quoting Katz v. United States, 389 U. S., at 361 (Harlan, J., concurring)). *189The mode of analysis that underlies this assertion is certainly more consistent with our prior decisions than that discussed above. But the Court’s conclusion cannot withstand scrutiny.
As the Court acknowledges, we have traditionally looked to a variety of factors in determining whether an expectation of privacy asserted in a physical space is “reasonable.” Ante, at 177-178. Though those factors do not lend themselves to precise taxonomy, they may be roughly grouped into three categories. First, we consider whether the expectation at issue is rooted in entitlements defined by positive law. Second, we consider the nature of the uses to which spaces of the sort in question can be put. Third, we consider whether the person claiming a privacy interest manifested that interest to the public in a way that most people would understand and respect.8 When the expectations of privacy asserted by petitioner Oliver and respondent Thornton9 are examined through these lenses, it becomes clear that those expectations are entitled to constitutional protection.
A
We have frequently acknowledged that privacy interests are not coterminous with property rights. E. g., United States v. Salvucci, 448 U. S. 83, 91 (1980). However, because “property rights reflect society’s explicit recognition *190of a person’s authority to act as he wishes in certain areas, [they] should be considered in determining whether an individual’s expectations of privacy are reasonable.” Rakas v. Illinois, 439 U. S. 128, 153 (1978) (Powell, J., concurring).10 Indeed, the Court has suggested that, insofar as “[o]ne of the main rights attaching to property is the right to exclude others, . . . one who owns or lawfully possesses or controls property will in all likelihood have a legitimate expectation of privacy by virtue of this right to exclude.” Id., at 144, n. 12 (opinion of the Court).11
It is undisputed that Oliver and Thornton each owned the land into which the police intruded. That fact alone provides considerable support for their assertion of legitimate privacy interests in their woods and fields. But even more telling is the nature of the sanctions that Oliver and Thornton could invoke, under local law, for violation of their property rights. In Kentucky, a knowing entry upon fenced or otherwise enclosed land, or upon unenclosed land conspicuously posted with signs excluding the public, constitutes criminal trespass. Ky. Rev. Stat. §§ 511.070(1), 511.080, 511.090(4) (1975). The law in Maine is similar. An intrusion into “any place from *191which [the intruder] may lawfully be excluded and which is posted in a manner prescribed by law or in a manner reasonably likely to come to the attention of intruders or which is fenced or otherwise enclosed” is a crime. Me. Rev. Stat. Ann., Tit. 17A, §402(1)(C) (1964).12 Thus, positive law not only recognizes the legitimacy of Oliver’s and Thornton’s insistence that strangers keep off their land, but subjects those who refuse to respect their wishes to the most severe of penalties — criminal liability. Under these circumstances, it is hard to credit the Court’s assertion that Oliver’s and Thornton’s expectations of privacy were not of a sort that society is prepared to recognize as reasonable.
B
The uses to which a place is put are highly relevant to the assessment of a privacy interest asserted therein. Rakas v. Illinois, supra, at 153 (POWELL, J., concurring). If, in light of our shared sensibilities, those activities are of a kind in which people should be able to engage without fear of intrusion by private persons or government officials, we extend the protection of the Fourth Amendment to the space in question, even in the absence of any entitlement derived from positive law. E. g., Katz v. United States, 389 U. S., at 352-353.13
*192Privately owned woods and fields that are not exposed to public view regularly are employed in a variety of ways that society acknowledges deserve privacy. Many landowners like to take solitary walks on their property, confident that they will not be confronted in their rambles by strangers or policemen. Others conduct agricultural businesses on their property.14 Some landowners use their secluded spaces to meet lovers, others to gather together with fellow worship-pers, still others to engage in sustained creative endeavor. Private land is sometimes used as a refuge for wildlife, where flora and fauna are protected from human intervention of any kind.15 Our respect for the freedom of landowners to use *193their posted “open fields” in ways such as these partially explains the seriousness with which the positive law regards deliberate invasions of such spaces, see supra, at 190-191, and substantially reinforces the landowners’ contention that their expectations of privacy are “reasonable.”
C
Whether a person “took normal precautions to maintain his privacy” in a given space affects whether his interest is one protected by the Fourth Amendment. Rawlings v. Kentucky, 448 U. S. 98, 105 (1980).16 The reason why such precautions are relevant is that we do not insist that a person who has a right to exclude others exercise that right. A claim to privacy is therefore strengthened by the fact that the claimant somehow manifested to other people his desire that they keep their distance.
Certain spaces are so presumptively private that signals of this sort are unnecessary; a homeowner need not post a “Do Not Enter” sign on his door in order to deny entrance to uninvited guests.17 Privacy interests in other spaces are more ambiguous, and the taking of precautions is consequently more important; placing a lock on one’s footlocker strengthens one’s claim that an examination of its contents is impermissible. See United States v. Chadwick, 433 U. S., at 11. Still other spaces are, by positive law and social convention, presumed accessible to members of the public unless the owner manifests his intention to exclude them.
Undeveloped land falls into the last-mentioned category. If a person has not marked the boundaries of his fields or woods in a way that informs passersby that they are not wel*194come, he cannot object if members of the public enter onto the property. There is no reason why he should have any greater rights as against government officials. Accordingly, we have held that an official may, without a warrant, enter private land from which the public is not excluded and make observations from that vantage point. Air Pollution Variance Board v. Western Alfalfa Corp., 416 U. S. 861, 865 (1974). Fairly read, the case on which the majority so heavily relies, Hester v. United States, 265 U. S. 57 (1924), affirms little more than the foregoing unremarkable proposition. From aught that appears in the opinion in that case, the defendants, fleeing from revenue agents who had observed them committing a crime, abandoned incriminating evidence on private land from which the public had not been excluded. Under such circumstances, it is not surprising that the Court was unpersuaded by the defendants’ argument that the entry onto their fields by the agents violated the Fourth Amendment.18
A very different case is presented when the owner of undeveloped land has taken precautions to exclude the public. As indicated above, a deliberate entry by a private citizen onto private property marked with “No Trespassing” signs will expose him to criminal liability. I see no reason why a government official should not be obliged to respect such *195unequivocal and universally understood manifestations of a landowner’s desire for privacy.19
In sum, examination of the three principal criteria we have traditionally used for assessing the reasonableness of a person’s expectation that a given space would remain private indicates that interests of the sort asserted by Oliver and Thornton are entitled to constitutional protection. An owner’s right to insist that others stay off his posted land is firmly grounded in positive law. Many of the uses to which such land may be put deserve privacy. And, by marking the boundaries of the land with warnings that the public should not intrude, the owner has dispelled any ambiguity as to his desires.
The police in these cases proffered no justification for their invasions of Oliver’s and Thornton’s privacy interests; in neither case was the entry legitimated by a warrant or by one of the established exceptions to the warrant requirement. I conclude, therefore, that the searches of their land violated the Fourth Amendment, and the evidence obtained in the course of those searches should have been suppressed.
HH t — i
A clear, easily administrable rule emerges from the analysis set forth above: Private land marked in a fashion sufficient to render entry thereon a criminal trespass under the law of the State in which the land lies is protected by the Fourth Amendment’s proscription of unreasonable searches and seizures. One of the advantages of the foregoing rule is that *196it draws upon a doctrine already familiar to both citizens and government officials. In each jurisdiction, a substantial body of statutory and case law defines the precautions a landowner must take in order to avail himself of the sanctions of the criminal law. The police know that body of law, because they are entrusted with responsibility for enforcing it against the public; it therefore would not be difficult for the police to abide by it themselves.
By contrast, the doctrine announced by the Court today is incapable of determinate application. Police officers, making warrantless entries upon private land, will be obliged in the future to make on-the-spot judgments as to how far the curtilage extends, and to stay outside that zone.20 In addition, we may expect to see a spate of litigation over the question of how much improvement is necessary to remove private land from the category of “unoccupied or undeveloped area” to which the “open fields exception” is now deemed applicable. See ante, at 180, n. 11.
The Court’s holding not only ill serves the need to make constitutional doctrine “workable for application by rank- and-file, trained police officers,” Illinois v. Andreas, 463 U. S. 765, 772 (1983), it withdraws the shield of the Fourth Amendment from privacy interests that clearly deserve protection. By exempting from the coverage of the Amendment large areas of private land, the Court opens the way to investigative activities we would all find repugnant. Cf., e. g., United States v. Lace, 669 F. 2d 46, 54 (CA2 1982) (Newman, J., concurring in result) (“[WJhen police officers execute military maneuvers on residential property for three weeks of round-the-clock surveillance, can that be called frea-*197sonable’?”); State v. Brady, 406 So. 2d 1093, 1094-1095 (Fla. 1981) (“In order to position surveillance groups around the ranch’s airfield, deputies were forced to cross a dike, ram through one gate and cut the chain lock on another, cut or cross posted fences, and proceed several hundred yards to their hiding places”), cert. granted, 456 U. S. 988, supplemental memoranda ordered and oral argument postponed, 459 U. S. 986 (1982).21
The Fourth Amendment, properly construed, embodies and gives effect to our collective sense of the degree to which men and women, in civilized society, are entitled “to be let alone” by their governments. Olmstead v. United States, 277 U. S. 438, 478 (1928) (Brandeis, J., dissenting); cf. Smith v. Maryland, 442 U. S., at 750 (Marshall, J., dissenting). The Court’s opinion bespeaks and will help to promote an impoverished vision of that fundamental right.
I dissent.
The Court informs us that the Framers would have understood the term “effects” to encompass only personal property. Ante, at 177, n. 7. Such a construction of the term would exclude both a public phone booth and spoken words.
On the other hand, an automobile surely does constitute an “effect.” Under the Court’s theory, cars should therefore stand on the same constitutional footing as houses. Our cases establish, however, that car owners’ diminished expectations that their cars will remain free from prying eyes warrants a corresponding reduction in the constitutional protection accorded cars. E. g., United States v. Martinez-Fuerte, 428 U. S. 543, 561 (1976).
By their terms, the provisions of the Bill of Rights curtail only activities by the Federal Government, see Barron v. Mayor and City Council of Baltimore, 7 Pet. 243 (1833), but the Fourteenth Amendment subjects state and local governments to the most important of those restrictions, see, e. g., Cantwell v. Connecticut, 310 U. S. 296 (1940) (First Amendment); Wolf v. Colorado, 338 U. S. 25 (1949) (Fourth Amendment).
Cf. McCulloch v. Maryland, 4 Wheat. 316, 407 (1819) (“[W]e must never forget, that it is a constitution we are expounding.” Such a document cannot be as detailed as a “legal code”; “[i]ts nature . . . requires, that only its great outlines should be marked, its important objects designated, and the minor ingredients which compose those objects be deduced from the nature of the objects themselves”) (emphasis in original).
Our rejection of the mode of interpretation appropriate for statutes is perhaps clearest in our treatment of the First Amendment. That Amendment provides, in pertinent part, that “Congress shall make no law . . . abridging the freedom of speech, or of the press” but says nothing, for example, about restrictions on expressive behavior or about access to the courts. Yet, to give effect to the purpose of the Amendment, we have applied it to regulations of conduct designed to convey a message, e. g., Edwards v. South Carolina, 372 U. S. 229 (1963), and have accorded constitutional protection to the public’s “right of access to criminal trials,” Globe Newspaper Co. v. Superior Court, 467 U. S. 596, 604-605 (1982).
See also United States v. Chadwick, 433 U. S. 1, 7, 11 (1977) (disagreeing with the suggestion that the Fourth Amendment “protects only dwellings and other specifically designated locales”; asserting instead that the purpose of the Amendment “is to safeguard individuals from unreasonable government invasions of legitimate privacy interests”); Rakas v. Illinois, 439 U. S. 128, 143 (1978) (holding that the determinative question is “whether the person who claims the protection of the Amendment has a legitimate expectation of privacy in the invaded place”).
Our most recent decisions continue to rely on the conception of the purpose and scope of the Fourth Amendment that we enunciated in Katz. See, e. g., United States v. Jacobsen, ante, at 113-118; Michigan v. Clifford, 464 U. S. 287, 292-293 (1984); Illinois v. Andreas, 463 U. S. 765, 771 (1983); United States v. Place, 462 U. S. 696, 706-707 (1983); Texas v. Brown, 460 U. S. 730, 738-740 (1983) (plurality opinion); United States v. Knotts, 460 U. S. 276, 280-281 (1983).
Sensitive to the weakness of its argument that the “persons or things” mentioned in the Fourth Amendment exhaust the coverage of the provision, the Court goes on to analyze at length the privacy interests that might legitimately be asserted in “open fields.” The inclusion of Parts III and IV in the opinion, coupled with the Court’s reaffirmation of Katz and its progeny, ante, at 177, strongly suggests that the plain-language theory sketched in Part II of the Court’s opinion will have little or no effect on our future decisions in this area.
The privacy interests protected by the Fourth Amendment are not limited to expectations that physical areas will remain free from public and government intrusion. See supra, at 187-188. The factors relevant to the assessment of the reasonableness of a nonspatial privacy interest may well be different from the three considerations discussed here. See, e. g., Smith v. Maryland, 442 U. S. 735, 747-748 (1979) (Stewart, J., dissenting); id., at 750-752 (MARSHALL, J., dissenting).
The Court does not dispute that Oliver and Thornton had subjective expectations of privacy, nor could it in view of the lower courts’ findings on that issue. See United States v. Oliver, No. CR80-00005-01-BG (WD Ky., Nov. 14, 1980), App. to Pet. for Cert. in No. 82-15, pp. 19-20; Maine v. Thornton, No. CR82-10 (Me. Super. Ct., Apr. 16, 1982), App. to Pet. for Cert. in No. 82-1273, pp. B-4 — B-5.
The Court today seeks to evade the force of this principle by contending that the law of property is designed to serve various “prophylactic” and “economic” purposes unrelated to the protection of privacy. Ante, at 183-184, and n. 15. Such efforts to rationalize the distribution of entitlements under state law are interesting and may have some explanatory power, but cannot support the weight the Court seeks to place upon them. The Court surely must concede that one of the purposes of the law of real property (and specifically the law of criminal trespass, see infra, this page and 191, and n. 12) is to define and enforce privacy interests — to empower some people to make whatever use they wish of certain tracts of land without fear that other people will intrude upon their activities. The views of commentators, old and new, as to other functions served by positive law are thus insufficient to support the Court’s sweeping assertion that “in the case of open fields, the general rights of property. . . have little or no relevance to the applicability of the Fourth Amendment,” ante, at 183-184.
See also Rawlings v. Kentucky, 448 U. S. 98, 112 (1980) (Blackmun, J., concurring).
Cf. Comment to ALI, Model Penal Code §221.2, p. 87 (1980) (“The common thread running through these provisions [a sample of state criminal trespass laws] is the element of unwanted intrusion, usually coupled with some sort of notice to would-be intruders that they may not enter. Most people do not object to strangers tramping through woodland or over pasture or open range. On the other hand, intrusions into buildings, onto property fenced in a manner manifestly designed to exclude intruders, or onto any private property in defiance of actual notice to keep away is generally considered objectionable and under some circumstances frightening”).
In most circumstances, this inquiry requires analysis of the sorts of uses to which a given space is susceptible, not the manner in which the person asserting an expectation of privacy in the space was in fact employing *192it. See, e. g., United States v. Chadwick, 433 U. S., at 13. We make exceptions to this principle and evaluate uses on a case-by-case basis in only two contexts: when called upon to assess (what formerly was called) the “standing” of a particular person to challenge an intrusion by government officials into a area over which that person lacked primary control, see, e. g., Rakas v. Illinois, 439 U. S., at 148-149; Jones v. United States, 362 U. S. 267, 265-266 (1960), and when it is possible to ascertain how a person is using a particular space without violating the very privacy interest he is asserting, see, e. g., Katz v. United States, 389 U. S., at 352. (In eases of the latter sort, the inquiries described in this Part and in Part II-C, infra, are coextensive). Neither of these exceptions is applicable here. Thus, the majority’s contention that, because the cultivation of marihuana is not an activity that society wishes to protect, Oliver and Thornton had no legitimate privacy interest in their fields, ante, at 182-183, and n. 13, reflects a misunderstanding of the level of generality on which the constitutional analysis must proceed.
We accord constitutional protection to businesses conducted in office buildings, see supra, at 185-186; it is not apparent why businesses conducted in fields that are not open to the public are less deserving of the benefit of the Fourth Amendment.
This last-mentioned use implicates a kind of privacy interest somewhat different from those to which we are accustomed. It involves neither a person’s interest in immunity from observation nor a person’s interest in shielding from scrutiny the residues and manifestations of his personal life. Cf. Weinreb, Generalities of the Fourth Amendment, 42 U. Chi. L. Rev. 47, 52-54 (1974). It derives, rather, from a person’s desire to preserve inviolate a portion of his world. The idiosyncracy of this interest does not, however, render it less deserving of constitutional protection.
See also Rakas v. Illinois, supra, at 152 (Powell, J., concurring); United States v. Chadwick, supra, at 11; Katz v. United States, supra, at 352.
However, if the homeowner acts affirmatively to invite someone into his abode, he cannot later insist that his privacy interests have been violated. Lewis v. United States, 385 U. S. 206 (1966).
An argument supportive of the position taken by the Court today might be constructed on the basis of an examination of the record in Hester. It appears that, in his approach to the house, one of the agents crossed a pasture fence. See Tr. of Record in Hester v. United States, O. T. 1923, No. 243, p. 16. However, the Court, in its opinion, placed no weight upon — indeed, did not even mention — that circumstance.
In any event, to the extent that Hester may be read to support a rule any broader than that stated in Air Pollution Variance Board v. Western Alfalfa Corp., 416 U. S. 861 (1974), it is undercut by our decision in Katz, which repudiated the locational theory of the coverage of the Fourth Amendment enunciated in Olmstead v. United States, 277 U. S. 438 (1928), and by the line of decisions originating in Katz, see supra, at 187-188, and n. 6.
Indeed, important practical considerations suggest that the police should not be empowered to invade land closed to the public. In many parts of the country, landowners feel entitled to use self-help in expelling trespassers from their posted property. There is thus a serious risk that police officers, making unannounced, warrantless searches of “open fields,” will become involved in violent confrontations with irate landowners, with potentially tragic results. Cf. McDonald v. United States, 335 U. S. 451, 460-461 (1948) (Jackson, J., concurring).
The likelihood that the police will err in making such judgments is suggested by the difficulty experienced by courts when trying to define the curtilage of dwellings. See, e. g., United States v. Berrong, 712 F. 2d 1370, 1374, and n. 7 (CA11 1983), cert. pending, No. 83-988; United States v. Van Dyke, 643 F. 2d 992, 993-994 (CA4 1981).
Perhaps the most serious danger in the decision today is that, if the police are permitted routinely to engage in such behavior, it will gradually become less offensive to us all. As Justice Brandéis once observed: “Our Government is the potent, the omnipresent teacher. For good or for ill, it teaches the whole people by its example. Crime is contagious. If the Government becomes a lawbreaker, it breeds contempt for law. . . .” Olmstead v. United States, 277 U. S., at 485 (dissenting opinion). See also Solem v. Stumes, 465 U. S. 688, 667 (1984) (Stevens, J., dissenting).