There are 6 US Post Offices in Grant County serving a total of 10,819 residents equating to 1,803 residents per post office. It's estimated that approximately 17,268 packages are handled across the 6 county post offices annually. Grant County is a county located in the U.S. state of West Virginia. As of the 2010 census, the population was 11,937. Its county seat is Petersburg. The county was created from Hardy County in 1866 and named for General Ulysses Simpson Grant. After the American Civil War, there was an effort by former Confederates to name it 'Lee County' instead after General Robert E. Lee, but the effort proved fruitless. Most of the 47 people killed in the 1985 Election day floods were in Pendleton and Grant counties, according to the National Weather Service. At Franklin, the Pendleton County seat, the South Branch of the Potomac River crested at 22.6 feet during the incident. Flood stage in the shallow riverbed was only 7 feet."