Lake Thompson is one of the largest natural lakes in South Dakota, spanning approximately 15,000 acres with over 40 miles of shoreline. Located in east-central South Dakota near De Smet, this expansive water body features rocky shorelines and submerged timber that create excellent fish habitat. The lake's size is highly variable, having been completely dry during the 1930s, while growing to cover as much as 20,000 acres in the early 1990s. Lake Thompson is a significant fishery in the state, hosting numerous walleye tournaments throughout the year and offering anglers opportunities to target multiple game fish species. Its basin-type structure and diverse underwater features make it an attractive destination for both novice and experienced anglers year-round.