Bryn Mawr (pronounced /ˌbrɪnˈmɑːr/; from Welsh for "big hill") is a census-designated place (CDP) in Radnor Township, Delaware County, Pennsylvania, Haverford Township, Delaware County, Pennsylvania and Lower Merion Township, Montgomery County, Pennsylvania, just west of Philadelphia along Lancaster Avenue (US-30) and the border with Delaware County. Bryn Mawr is located toward the center of what is known as the Main Line, a group of affluent Philadelphia suburbs stretching from the city limits to Malvern.