There are 30 US Post Offices in Butler County serving a total of 166,969 residents equating to 5,566 residents per post office. It's estimated that approximately 266,501 packages are handled across the 30 county post offices annually. Butler County is a county located in the U.S. state of Pennsylvania. As of the 2010 census, the population was 183,862. Its county seat is Butler. Butler County was created on March 12, 1800, from part of Allegheny County and named in honor of General Richard Butler, a hero of the American Revolution. Butler County is included in the Pittsburgh, PA Metropolitan Statistical Area."