Meridian is a census-designated place (CDP) in Butler County, Pennsylvania, United States. The population was 3,794 at the 2000 census.
Meridian was linked to Butler, Evans City and Pittsburgh in 1908 by the Pittsburgh, Harmony, Butler and New Castle Railway, an interurban trolley line. The line closed on 15 June 1931 and the trolleys were replaced by buses.
Meridian is located at 40°51′16″N 79°57′23″W / 40.85444°N 79.95639°W / 40.85444; -79.95639 (40.854415, -79.956359).