There are 7 US Post Offices in Nemaha County serving a total of 9,860 residents equating to 1,409 residents per post office. It's estimated that approximately 15,738 packages are handled across the 7 county post offices annually. Nemaha County (standard abbreviation: NM) is a county located in the northeastern part of the U.S. state of Kansas. As of the 2010 census, the county population was 10,178. The county seat is Seneca."