Deuel County is a county in the U.S. state of South Dakota. As of the 2020 census, the population was 4,295. Its county seat is Clear Lake. The county was created in 1862, and was organized in 1878. It is named for Jacob Deuel, a legislator in 1862.

Interstate 29 (I-29) is a north–south Interstate Highway in the midwestern United States. In the state of South Dakota, I-29 traverses on the eastern side of the state from the Iowa border near Sioux City to the North Dakota border near New Effington. On its route, I-29 passes through western portions of Sioux Falls, the state's largest city. It travels 252.5 miles (406.4 km) in the state, the longest stretch of any of the four states through which it passes. I-229, the highway's lone auxiliary route in South Dakota, serves as a bypass around southern and eastern Sioux Falls.