There are 3 US Post Offices in Mcdowell County serving a total of 45,273 residents equating to 15,091 residents per post office. It's estimated that approximately 72,261 packages are handled across the 3 county post offices annually. McDowell County is a county located in the U.S. state of North Carolina. As of the 2010 census, the population was 44,996. Its county seat is Marion. McDowell County comprises the Marion, NC Micropolitan Statistical Area, which is also included in the Hickory-Lenoir, NC Combined Statistical Area.