Conestoga High School, located in Tredyffrin Township, Pennsylvania, is the only upper secondary school in the Tredyffrin/Easttown School District. It has a Berwyn post office address, though it is not in the Berwyn census-designated place. Conestoga, commonly referred to as "Stoga", is 20 miles (32 km) northwest of Philadelphia in the suburbs known as the Main Line. Wikipedia