There are 7 US Post Offices in Nelson County serving a total of 3,343 residents equating to 478 residents per post office. It's estimated that approximately 5,336 packages are handled across the 7 county post offices annually. Nelson County is a county located in the U.S. state of North Dakota. As of the 2010 census, the population was 3,126. Its county seat is Lakota. The county was founded in 1883."