The 166th Pennsylvania House of Representatives District is located in Delaware County and Montgomery County and includes the following areas: * Delaware County * Haverford Township (PART, Wards 02, 03, 04, 05, 06, 07 and 08) * Radnor Township (PART) * Ward 01 [PART, Division 02] * Ward 02 * Ward 03 [PART, Division 02] * Ward 05 [PART, Division 01] * Ward 07 * Montgomery County * Lower Merion Township (PART) * Ward 04 * Ward 08 * Ward 10 [PART, Division 03]