24 Pa. Stat. § 13-1312
In any district of the fourth class or any district of the third class, which is located wholly within the boundary lines of a township, or within the boundary lines of a borough which has a population of less than five hundred (500) inhabitants to the square mile, elementary school pupils who reside within that part of the school district last served by any elementary school closed since the first Monday of July, one thousand nine hundred seven, or within a district all of whose schools have been closed, or who are assigned to a training school of a State teachers' college, and reside one and one-half miles or more from the school to which they are assigned, shall be furnished proper transportation, at the expense of the district, to and from the elementary school to which they are assigned.
24 P.S. § 13-1312