after making the foregoing statement, delivered the opinion of the court.

At the .outset, we premise that, as the grant of the right of way, the filing of the map of definite location, and the construction of the railroad within the quarter section in question preceded the filing of the homestead entries on such section, the land forming the right of way therein was taken out of the category .of public.lands subject to preemption and sale, and the land department was therefore without authority to convey rights therein. It follows that the homesteaders acquired no interest in the land within the- right of way because of the fact that the grant to them was of the full legal subdivisions.

Conceding the adverse possession and its efficacv' under the state law as against the railroad right of way, to be as found by the state court, the ■ sole question which arises then for decision is whether, in view of the provisions of the act of Congress to which we have referred, an asserted title by adverse possession can be made efficacious as respects the property in controversy. And depending, as this question does, upon the nature and effect of the acts of Congress, its solution necessarily involves a Federal question.

In determining whether an individual, for private purposes may, by adverse possession, under a state statute of limitations, acquire title toa portion of the light of way granted’by the United States for the use of this railroad, we must be guided by the doctrine enunciated in Packer v. Bird, 137 U. S. 661, 669, and approvingly referred to in Shively v. Bowlby, 152 U. S. 1, 44, viz.: “ The courts of the United States will construe the grants of the general government without reference to the rules of construction adopted by the States "for their grants; but whatever incidents or rights attach to the owner[*271] ship of property conveyed by tbe government will be determined by tbe States, subject.to tbe condition that tbeir rules do not impair tbe efficacy of tbe grants or tbe use and enjoyment of tbe própérty by tbe grantee.” Following decisions of this court construing grants of rights of way similar in tenor to tbe grant now being considered, New Mexico v. United States Trust Co., 172 U. S. 171, 181; St. Joseph & Denver City R. R. Co. v. Baldwin, 103 U. S. 426, it must be held that tbe fee passed by tbe grant made in section 2 of tbe act of July 2,. 1864. But, although there was a present grant,' it was ‘yet subject to conditions expressly stated in the act, and also (to quote tbe language of tbe Baldwin case) “ to those necessarily implied, such as that tbe road shall be . . . used for the purposes designed.” Manifestly, the land forming the right, of way was not granted with tbe intent that it might be absolutely disposed of at tbe volition of the company. On tbe contrary, the grant .was explicitly stated to be for a designated’ purpose, one which negated tbe existence of the power to voluntarily alienate tbe right of way or any portion thereof. Tbe substantial consideration inducing the grant was tbe perpetual use of tbe land for the legitimate purposes of the railroad,'just as though the land bad been conveyed in terms to have and. to bold tbe same so long as it was used for the railroad right of way. In effect tbe grant was of a limited fee, made on an implied condition of reverter in tbe event that the company ceased to use or retain the land for the purpose for which it was granted. This being tbe nature of the title to the land granted for the special purpose named, it is évident that to give such efficacy to a statute of limitations of a State as would operate to confer a permanent right of possession to any portion thereof upon an individual for bis private use, would be to allow that to be done by indirection which could not be done directly, for, as said in Grand Trunk Railroad v. Richardson, 91 U. S. 454, 468, “ a railroad company is not at liberty to alienate any part of its roadway so as to interfere with tbe full exercise of tbe franchises granted.” . Nor can it be rightfully contended that tbe portion of tbe right of way appropriated was not necessary for the execution of the powers con-[*272] ferfed by Congress, for, as said in Northern Pacific Railroad Co. v. Smith, 171 U. S. 261, 275, speaking of the very grant under consideration: “ By granting a right of way four hundred feet in width, Congress must be understood to have conclusively determined that a strip of that width was necessary for a public work of such importance.” Neither courts nor juries, therefore, nor the general public, may be permitted to conjecture that a portion of such right of Way is no longer needed for the use of the railroad and title to it has vested in whomsoever chooses to occupy the same. The whole of the granted right of way must be presumed to be necessary for the purposes of the railroad, as against a claim by an individual of an exclusive right qf possession for private purposes.

To repeat, the right of way was given in order that the obligations .to the United States assumed in the acceptance of the act might be performed. Congress having plainly manifested its intention that the title. to and possession of the right of way should continue in the original grantee, its successors and assigns, so long as the railroad was maintained, the possession by individuals of portions of the right of way cannot be treated without overthrowing the act of Congress as forming the basis of an adverse possession which may ripen into a title good as against the railroad company.

Of course, nothing that has been said in anywise imports that a right of way granted through the public domain within a State is not amenable to the police power of the State. Congress must have assumed when making this grant, for instance, that in the natural order of events, as settlements were made along the line of the railroad, crossings of the right of way would become necessary, and that other limitations in favor of the general public upon an exclusive right of occupancy by the railroad of its right of way might be justly imposed. But such limitations are in no sense analogous to claim of adverse ownership for private use.

As our construction of the act of Congress determines the question presented for decision, it becomes unnecessary to review the cases which have been called to our attention supporting on the one hand or denying on the other the broad conten[*273] tion that title by adverse possession, under state statutes of limitation, may be acquired by individuals to .land within the right of way of a railroad. None of the cases adverted to as holding the affirmative of the proposition even suggest that the rule would be applicable where its enforcement would conflict with the powers and duties imposed by law on a railroad corporation in a given case. As here we find that the nature of the duties imposed by Congress upon the .railroad company and the character of the title conferred by Congress in giving the right of way through the public domain are inconsistent with the power in an individual to acquire, for private purposes, by limitation, a portion of the right of way granted by Congress, the cases in question are inapposite.

The judgment of the Supreme Court of Minnesota must be

Reversed, and the case remanded to that court for further ¡proceedings not inconsistent with this opinion.