Travelers are voting Fort Randall Dam as the best dam in Gregory County. There are 1 dam near Wagner a city just 44 km from Gregory County and 1 dam near Fort Pierre which is 92 km distant. The most popular of these are Fort Randall Dam near Wagner and Oahe Dam in Fort Pierre. You can find 4 dams in South Dakota and 138 dams in the country of United States. Our members favorite in South Dakota is Oahe Dam and Hoover Dam is the top pick in United States. Want more? Check out our map of dams in Gregory County.