delivered the opinion of the Court:
We regard it as unnecessary to review the many decisions; relating to mandamus against a public officer, that have been cited on the argument. The law, as said by Mr. Justice Peck-ham, “is well settled in the abstract, the only doubt which arises being whether the facts regarding any particular case bring, it within the law which permits the writ to issue where a mere¡ ministerial duty is imposed upon an executive officer, which, duty he is bound to perform without any further question. I£ he refuse under such circumstances, mandamus will lie to compel him to perform his duty.” Roberts v. United States, 176 U. S. 221, 229, 44 L. ed. 443, 446, 20 Sup. C. Rep. 376.
In this case there were no facts necessary to be ascertained by the Secretary in the performance of his duties. With his-approval, the relator had been enrolled as a member of the tribe entitled to an allotment of land. All the steps under the law and his regulations prescribing the procedure in accordance, therewith had been taken with due regularity, and ended in the execution of the patent by the persons charged with that duty. This patent, passing into the possession of the Secretary, has been withheld by him with the declared intention to cancel it and segregate the lands embraced in it, to be laid out as an addition to the railway town site of Mill Creek, upon the assumption that such power had been conferred on him by the several statutes relating to the allotment of the Choctaw and Chickasaw Indian lands. It is not contended that power to that end has; been expressly conferred by the statutes, but is claimed under his construction of them, and that the necessary construction of the statutes in the performance of his duty required the exercise of judgment and discretion.
Undoubtedly there are many cases in which, when a public officer is called upon to perform an official act as a duty, the interpretation of statutory provisions relating thereto would require the exercise of judgment to such an extent as to take-his decision out of the category of a mere ministerial act. Unit*173ed States ex rel. Dunlap v. Black, 128 U. S. 40, 32 L. ed. 354, 9 Sup. Ct. Rep. 12, and cases therein cited and discussed.
The particular decision which, in that case, the court refused to control by mandamus, was one that had been made by the Commissioner of Pensions upon an application by a pensioner for an increase. He had to determine the right by the construction of some confusing provisions of different acts that had been passed from time to time relating to the increase of pensions upon many grounds. He had not only to construe the meaning of particular provisions, but the effect also of later acts upon the former ones. This was held to require something more than the performance of a mere ministerial duty. The broad proposition that, because courts are vested with no ■special appellate power in such cases, they will not interfere by mandamus with executive officers in the performance of their official duties in any case where those duties require an interpretation of the law, has been expressly denied in the recent ■case of Roberts v. United States, 176 U. S. 221, 231, 44 L. ed. 443, 447, 20 Sup. Ct. Rep. 376.
It was said in that case: “Every statute to some extent requires construction by the public officer whose duties may be defined therein. Such officer must read the law, and he must therefore, in a certain sense, construe it in order to form a judgment, from its language, as to what duty he is directed by the statute to perform. But that does not necessarily and in all cases make the duty of the officer anything other than a purely ministerial one. If the law direct him to perform an act in regard to which no discretion is committed to him, and which, upon the facts existing, he is bound to perform, then that act is ministerial, although depending upon a statute which requires, in some degree, a construction of its language by the officer. Unless this be so, the value of this writ is very greatly impaired. Every executive officer whose duty is plainly devolved upon him by statute might refuse to perform it, and when his refusal is brought before the court he might successfully plead that the performance of the duty involved the construction of a statute by him, and therefore it was not minis*174terial, and the court would on that account be powerless to give relief. Such a limitation of the powers of the court, we think,, would be most unfortunate, as it would relieve from judicial supervision all executive officers in the performance of their duties, whenever they should plead that the duty required of them arose upon the construction of a statute, no matter * * * how plainly they violated their duty in refusing to-perform the act required.”
In the light of the foregoing doctrine, we are of the opinion that the Secretary’s decision in respect of his powers, under the admitted facts of this case, did not require the exercise of judgment to such an extent as to place his action beyond the control of the court by mandamus. There were several statutes relating to the allotment of the Indian lands and the reservation of town sites, but there was no conflict between them and no confusion in their application. Later acts expressly re-enacted the provisions of former ones, that are relevant to the facts presented. As a matter of fact, there was no occasion to construe these acts at all, in order to perform the final act demanded of the Secretary, namely, the delivery of the patent. In so far as the relator’s rights are involved, all the requirements-of the statute have been fully and regularly performed. Whatever power of direction, supervision, or approval has been conferred upon the Secretary in respect of the allotment of the Indian lands, making regulations therefor, and the reservation of town site, had been completely exhausted so far as the relator’s allotment was concerned. His official duties had been performed. It is admitted that he had approved the relator’s enrolment as a member of the tribe entitled to an allotment of land; that she was in possession of the land selected by her, and made her application to the proper tribunal in regular form; and that after the expiration of the nine months permitted for contest of her application, none having been made, she had received her certificate of allotment. The statute made this certificate conclusive evidence of her right to the land, entitled her to have the Indian agent remove all persons therefrom that were objectionable to her, and declared that his acts in so *175doing shall not be controlled by the process of any court. Relator’s right to the land became vested, and the execution and delivery of the patent — the evidence of her legal title — were ministerial acts. Barney v. Dolph, 97 U. S. 652, 24 L. ed. 1063; Simmons v. Wagner, 101 U. S. 260, 261, 25 L. ed. 910, 911; United States v. Detroit Timber & Lumber Co. 200 U. S. 321, 325, 50 L. ed. 499, 501, 26 Sup. Ct. Rep. 282.
The patent to which relator was entitled under the certificate of allotment was in fact executed by the parties charged with that duty by the express terms of the statute. This patent passed into the hands of the Secretary, whose duty was to deliver it to the relator, as the statute conferred no power upon him to review the acts of the Commission, or to set aside the patent. United States v. Schurz, 102 U. S. 378, 395, 26 L. ed. 167, 171; United States ex rel. West v. Hitchcock, 19 App. D. C. 333, 344.
The contention, then, in support of the right to recall and vacate the patent and the certificate of allotment is reduced substantially to this: Under his construction of the statutes, the Secretary holds that the certificate and patent are not conclusive, and that his authority to segregate the land embraced therein as an addition to the Mill Creek town site remains unimpaired thereby. Undoubtedly the statutes had authorized the Secretary to set aside land for town sites, and he had repeatedly so done. The town site of Mill Creek was laid out and set apart as one of those along railway lines constructed or in process of construction. It is unimportant to consider the power of the Secretary, of his own motion, to make additions to the town -site, as it is not pretended that he had exorcised any such power. The act of March 31, 1900, heretofore recited, authorized the Commissioner to the Rive Civilized Tribes to recommend the reservation of additions to such town sites as Mill Creek, and this might be done “at any time before allotment.” Before allotment such a recommendation was made and transmitted to the Secretary. Had he given it his approval, no selection of the land would have been entertained, and no allotment of it could have been made. Instead of approving, he disapproved, the *176recommendation, thereby ending its efficacy. Grant that, as indicated in his notice of disapproval, private parties interested in the extension of the town site might have procured from the Secretary an order for the reservation and the incorporation of the additional lands before their allotment; but no action was taken by them. Some time after this disapproval and the failure of action by private parties, the relator selected the land, as she had the right to do. Her selection and application depended before the Commission for the nine months provided for objections to and contest of the right to the certificate of allotment. Throughout this period no reservation of the land for a town site was recommended or applied for, and there was no contest of the relator’s right. The certificate, declared by the statute conclusive evidence of the passage of the tribal right, was regularly issued, and the patent followed.
Afterwards the Secretary concluded that the recommendation for additional town sites ought to have been approved and the land reserved as an extension, in the interest of the town and ■the “urban occupants;” and from a natural desire to protect what he conceived to be the equitable rights of these occupants, he has examined the statutes, and from their construction decided that he has the power to cancel the patent and allotment, .and thereafter convert the land into a town site.
In our opinion, the statutes are plain, and admit of no room for construction. Believing that the Secretary’s power in the premises ended with the issue of the certificate of allotment and the patent, we think that he has no power to hold the patent for cancelation, and that it is his plain duty to deliver it to the relator.
The judgment will therefore be affirmed, with costs. It is so ordered.
Affirmed.
A writ of error to the Supreme Court of the United States was allowed December 13, 1907.