Bryn Mawr, from Welsh for 'big hill', is a census-designated place located across three townships: Radnor Township and Haverford Township in Delaware County and Lower Merion Township in Montgomery County, Pennsylvania, United States. It is located just west of Philadelphia along Lancaster Avenue, also known as U.S. Route 30. Bryn Mawr is located toward the center of what is known as the Main Line, a group of affluent Philadelphia suburban villages stretching from the city limits to Malvern.