There are 6 US Post Offices in Washington County serving a total of 31,595 residents equating to 5,266 residents per post office. It's estimated that approximately 50,429 packages are handled across the 6 county post offices annually. Washington County is a county located in the Commonwealth of Virginia. As of the 2010 census, the population was 54,876. Its county seat is Abingdon. Washington County is part of the Kingsport\u2013Bristol\u2013Bristol, TN-VA Metropolitan Statistical Area, which is a component of the Johnson City\u2013Kingsport\u2013Bristol, TN-VA Combined Statistical Area, commonly known as the \"Tri-Cities\" region."