The roadway runs parallel to PA 43 for all but one mile (1.6 km) of its length.

The route continues north to the Springhill Township community of Haydentown, where it intersects PA 43 at exit 4 via Rubles Mill Road.

[3][4] PA 857 is one of several state route numbers to have been assigned, decommissioned and then reassigned later in a different region.

The original PA 857 that was commissioned in 1928 ran for 24 miles along the Ohio River from Pittsburgh's Manchester neighborhood to Rochester in Beaver County.

The highway, in conjunction with a connecting secondary road in West Virginia, was designated to provide another route between Uniontown and Morgantown, West Virginia along what was called "the back road to Morgantown".