There are 2 US Post Offices in Pleasants County serving a total of 7,025 residents equating to 3,513 residents per post office. It's estimated that approximately 11,213 packages are handled across the 2 county post offices annually. Pleasants County is a county located in the U.S. state of West Virginia. At the 2010 census, the population was 7,605, making it the third-least populous county in the state. Its county seat is St. Marys. The county was created by the Virginia General Assembly in 1851 and named for US Senator and Virginia Governor James Pleasants, Jr.."