64 Pa. Stat. § 141
No warrant or survey, to be issued or made in pursuance of this act, for lands lying north and west of the rivers Ohio and Allegheny, and Conewango creek, shall vest any title in or to the lands therein mentioned, unless the grantee has, prior to the date of such warrant, made, or caused to be made, or shall within the space of two years next after the date of the same, make or cause to be made an actual settlement thereon, by clearing, fencing and cultivating at least two acres for every hundred acres contained in one survey, erecting thereon a messuage for the habitation of man, and residing, or causing a family to reside thereon for the space of five years next following his first settling of the same, if he or she shall so long live; and that in default of such actual settlement and residence, it shall and may be lawful to and for this commonwealth to issue new warrants to other actual settlers for the said lands, or any part thereof, reciting the original warrants, and that actual settlements and residence have not been made in pursuance thereof, and so as often as default shall be made, for the time and in the manner aforesaid, which new grants shall be under and subject to all and every the regulations contained in this act: Provided always, nevertheless, That if any such actual settler, or any grantee in any such original or succeeding warrant, shall by force of arms of the enemies of the United States be prevented from making such actual settlement, or be driven therefrom, and shall persist in his endeavors to make such actual settlement as aforesaid, then, in either case, he and his heirs shall be entitled to have and to hold the said lands, in the same manner as if the actual settlement had been made and continued.
64 P.S. § 141