Devil's Lake State Park is a Wisconsin Department of Natural Resources property of roughly 9,217 acres wrapped around a spring-fed lake in the Baraboo Range, about three miles south of Baraboo in Sauk County. It is the most visited park in the Wisconsin state park system, with 2,384,606 visitors recorded in 2024. Two sand beaches sit at opposite ends of the lake and together run about 3,300 feet. Our pin is on the North Shore beach, the busier of the two, with the South Shore beach reachable from the park's south entrance off County Highway DL.

The lake fills a gap the ancient Wisconsin River cut straight through the Baraboo bluffs. Roughly 12,000 years ago the glacier dumped terminal moraines that plugged the gorge at both the north and south ends, and the trapped water became the lake. The walls left standing are Baraboo quartzite, a metamorphosed sandstone around 1.7 billion years old, rising about 500 feet above the water. The lake has no surface outlet and may drain underground toward the Baraboo River. Koshawago Spring feeds it from the southwest side. Water clarity is good enough that scuba divers use it, which is unusual for a southern Wisconsin lake.

Both beaches are groomed sand and shelve gradually. Away from the beaches the shoreline turns to quartzite cobble and loose talus, which is what the Tumbled Rocks Trail crosses on the west side. The DNR does not staff lifeguards during swimming hours, at either beach. The North Shore has a beach access mat and a beach wheelchair you can check out at the Chateau, the CCC-built stone and timber concession building above the sand. Concessions at both shores rent watercraft, including an adaptive kayak. Motors on the lake are restricted to electric only, life preservers are required for every occupant of every boat including rubber rafts, and scuba diving requires a dive flag and a buddy since solo dives are not allowed. There is a separate designated pet swim area near the south end, since dogs are kept off the main swim beaches.

Everything here runs on a Wisconsin state park vehicle admission sticker, required on any parked vehicle including roadside spots. As of the rate schedule effective August 19, 2025, a daily pass is $13 for Wisconsin plates and $16 for out-of-state plates. An annual sticker is $28 for Wisconsin residents, $13 for Wisconsin residents 65 and older, and $50 for non-residents. The park is open 6 a.m. to 11 p.m. year round. Both shore parking lots fill on hot summer weekends, often well before noon.

On water quality, be clear-eyed: this is an inland lake, so it falls outside the Great Lakes beach monitoring program, and the DNR does not run routine statewide testing for blue-green algae or its toxins. Blooms have been reported at Devil's Lake. Look at the water before you get in and skip it if you see discoloration, streaking, or floating scum, and report a significant bloom to DNRHABS@wisconsin.gov.

Camping is three family campgrounds, Quartzite, Northern Lights and Ice Age, plus a group camp, at more than 420 sites. Quartzite stays open year round while the other two generally close through winter. Sites are reserved through the DNR reservation system. Nearly 30 miles of trail climb the bluffs, including about 11 miles of the Ice Age National Scenic Trail, and lead to Devil's Doorway and Balanced Rock on the East Bluff. Parfrey's Glen, Wisconsin's oldest state natural area, is part of the park.