There are 7 US Post Offices in Wapello County serving a total of 35,575 residents equating to 5,082 residents per post office. It's estimated that approximately 56,782 packages are handled across the 7 county post offices annually. Wapello County is a county located in the U.S. state of Iowa. As of the 2010 census, the population was 35,625. The county seat is Ottumwa. The county was formed on February 17, 1843 and named for Wapello, a Meskwaki chief. Wapello County is included in the Ottumwa, IA Micropolitan Statistical Area."