There are 22 US Post Offices in Belmont County serving a total of 66,137 residents equating to 3,006 residents per post office. It's estimated that approximately 105,562 packages are handled across the 22 county post offices annually. Belmont County is a county located in the U.S. state of Ohio. As of the 2010 census, the population was 70,400. Its county seat is St. Clairsville. The county was created in 1801 and later organized in 1815. It takes its name from the French for \"beautiful mountain\". Belmont County is part of the Wheeling, WV-OH Metropolitan Statistical Area. It is the only Belmont County nationwide."