There are 4 US Post Offices in Edmunds County serving a total of 4,025 residents equating to 1,006 residents per post office. It's estimated that approximately 6,424 packages are handled across the 4 county post offices annually. Edmunds County is a county located in the U.S. state of South Dakota. As of the 2010 census, the population was 4,071. Its county seat is Ipswich. The county was established in 1873 and organized in 1883. It is named for Newton Edmunds, second Governor of Dakota Territory. Edmunds County is part of the Aberdeen, SD Micropolitan Statistical Area.