There are 14 US Post Offices in Minnehaha County serving a total of 157,922 residents equating to 11,280 residents per post office. It's estimated that approximately 252,061 packages are handled across the 14 county post offices annually. Minnehaha County is a county located along the eastern border in the state of South Dakota. As of the 2010 census, the population was 169,468, making it the most populous county in South Dakota. Its county seat is Sioux Falls, the largest city in the state. The county was created by European Americans in 1862 and organized in 1868. Its name was derived from the Sioux word Mnihaha, meaning \"rapid water,\" or \"waterfall\" (often also incorrectly translated as \"laughing water\"). Minnehaha County is part of the Sioux Falls, SD Metropolitan Statistical Area, the largest in the state. It is the site of a former listed Superfund site, the Williams Pipeline Company Disposal Site, which has been cleaned up under direction of the Environmental Protection Agency to contain and remove environmental hazards."