In fact, the Mount Rushmore State features miles of beaches
and acres of lake shore for sun, sand and summer adventure — like hiking treks in and around Sylvan Lake (photo, top left) considered the "crown jewel" in the array of attractions at Custer State Park. (Also don't miss Custer State Park's scenic swimming beach area at Stockade Lake just east of the park's west entrance along Highway 16A.)
More about South Dakota lake beaches around the Web:
Where are the South Dakota Beaches? - An avid camper has compiled a little list ... including every lake beach in locations from Aberdeen to Yankton, with photos and contact information.
Angostura Recreation Area - The hot springs located here have been battled over since the days of the Cheyenne, and today the area features a man-made lake with a swimming beach, boat launch, picnic shelter and campgrounds,
with more info included on area history, attractions, contact info.