Minnehaha County is a county located 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 county was created in 1862 and organized in 1868. It received its name from the Sioux  word Mnihaha, meaning "rapid water," or "waterfall" (often also incorrectly translated as "laughing water").