There are 6 US Post Offices in Deuel County serving a total of 4,475 residents equating to 746 residents per post office. It's estimated that approximately 7,143 packages are handled across the 6 county post offices annually. Deuel County (pronounced \"DOOL\") is a county located in the U.S. state of South Dakota. As of the 2010 census, the population was 4,364. Its county seat is Clear Lake. The county was created in 1862 and organized in 1878. It is named for Jacob Deuel, a legislator in 1862."