As of the date of the grant and conveyance aforesaid, a State highway is hereby established the route of which shall be as follows:
Beginning at a point on the boundary of the State of Pennsylvania, and to be selected and designated by the duly authorized officers and agents of the United States and the Secretary of Highways, and running thence along a line to be established by said officers and agents of the United States and the Secretary of Highways to the line of the lands so granted and conveyed.
74 P.S. § 103