There are 56 US Post Offices in Washington County serving a total of 298,550 residents equating to 5,331 residents per post office. It's estimated that approximately 476,519 packages are handled across the 56 county post offices annually. Washington County is a county located in the U.S. state of Pennsylvania. As of the 2010 census, the population was 207,820. Its county seat is Washington. The county was created on March 28, 1781, from part of Westmoreland County. The city and county were both named after American Revolutionary War leader George Washington, who eventually became the first President of the United States. Washington County is included in the Pittsburgh Metropolitan Statistical Area. The county is home to Washington County Airport, located three miles (5 km) southwest of Washington, Pennsylvania."