curves to cross Rays Hill, crossing into Fulton County, and coming to a pair of right-in/right-out ramps with the southern terminus of PA 915 in the unincorporated village of Crystal Spring, in Brush Creek Township. The freeway continues through a valley of farmland and comes to an eastbound rest area on the western slope of Town Hill, which the highway crosses at an oblique angle. In the middle of the mountain crossing, I-70 has another pair of right-in/right-out ramps with the northern terminus of PA 643, and then descends along the length of its eastern slope into another rural valley. Within this valley, the freeway enters Union Township, turns generally more southeast and interchanges with the northern terminus of PA 731, east of the unincorporated village of Amaranth. Past PA 731, I-70 crosses Sideling Hill and comes into Bethel Township. The route heads through forested and mountainous surroundings in the watershed of Tonoloway Creek, before coming to an interchange with the western end of the highway's concurrency with US 522 in the unincorporated town of Warfordsburg. Southbound US 522 merges onto eastbound I-70 and the two routes run concurrent across the Mason–Dixon line into Washington County, Maryland. History By 1947, present I-70 across Pennsylvania was included in the planned Interstate Highway System. The route from West Virginia split at Washington, with one branch heading northeast to meet the Pennsylvania Turnpike near Pittsburgh and the other heading east, bypassing Pittsburgh to the south (via a planned bypass of PA 71) to the New Stanton interchange. The piece south from the Breezewood interchange into Maryland was also in the network. The route between US 30 in Breezewood and US 522 in Warfordsburg was originally known as Pennsylvania Route 126 (PA 126). In 1957, preliminary numbers were assigned; the longer route via Pittsburgh (now I-79 and I-376) became the main line of I-70, while the southern bypass (now I-70) became Interstate 70S (I-70S). The section of present-day I-70 between PA 519 near Washington and New Stanton was built as a four-lane divided highway known as the "Express Highway"; this road was assigned the temporary PA 71 Alternate (PA 71 Alt.) designation in 1957 and would be designated as I-70S following the completion of additional connecting roads in the Interstate Highway System. On July 15, 1960, I-70 was designated onto the Penn-Lincoln Parkway. A southern extension of I-79 (which had previously only run from