Map of South Dakota Counties
There are a total of 66 counties in the state of South Dakota. Among them, Bon Homme County is the oldest one (established in 1862) while Jones County is the youngest (established in 1916). With population of 169,468, Minnehaha County is the most populated. The biggest county by land area is Meade County (8,990 km2) and the smallest is Clay County (1,067 km2).