Almost everything written about Castle Rock Lake describes the Juneau County half of its 70 or so miles of shoreline: Buckhorn State Park, the west-shore bars, the rental docks near Mauston. The other half belongs to Adams County, and its mailing addresses say Friendship. This guide is the lake from that side, the east shore, where the county park, the taco place on the water and the old taverns along County Road Z are.
What is Castle Rock Lake?
Castle Rock Lake is a reservoir on the Wisconsin River and the fourth-largest lake in Wisconsin, created when the Castle Rock Dam was finished in 1951. It covers roughly 16,000 acres across Adams and Juneau counties, and for all that water it is shallow, about 12 feet deep on average and 35 feet at its deepest.
Sponsored
The Wisconsin River Power Company started building the dams that made Castle Rock and its upstream neighbor, Lake Petenwell, in 1947, and both dams were built on sand, one of the first projects of that kind in the United States. The company still runs Castle Rock Dam for power.
One thing visitors often get wrong: the two lakes are not connected for boats. The Petenwell Dam sits between them and the Castle Rock Dam sits below, so you cannot boat from Petenwell into Castle Rock or on down the river toward the Dells.
Castle Rock Park, the east-shore base
Adams County Castle Rock Park, at 2397 County Road Z, is the public base on this side: 141 acres on the lake with a boat launch, a swimming area, a campground and a visitor center that stays open all year.
Don't confuse it with Juneau County Castle Rock Park, a separate and bigger park on the far side of the lake near Mauston, at 160 acres with more than 300 campsites, a swimming beach and a $5 day-use pass. The local land office spells it out on its own map page, because people mix the two up all the time.
Getting on the water
The simplest way onto the lake from the Friendship side is the launch at Castle Rock Park, and if you do not have a boat, the nearest pontoon rental is six miles north of the park in Arkdale.
Big Papa’s Pontoon Rentals rents pontoons for Castle Rock Lake out of Arkdale, and the staff send you off with a map, tips on where to go and which areas to avoid, and the option of a hired driver if your group would rather not captain. It opens at 8 a.m. most days.
On the Juneau side near Mauston, Castle Rock Watersports rents kayaks, canoes, stand-up paddleboards and floating lily pad mats. Customers suggest booking a longer window, eight hours rather than four, and Travel Wisconsin says to reserve pontoons ahead in summer.
Expect company on summer Saturdays. The lake draws heavy motorboat traffic at the weekend, and toward the north end, where the Wisconsin River comes in, the channel narrows to as little as 25 yards in places, so paddlers and boaters end up in close quarters.
Planning an east-shore day
A good east-shore day starts with breakfast inland, a launch or a swim at Castle Rock Park by mid-morning, and dinner on the water. A few practical details make it easier.
Castle Rock Park takes credit and debit cards, welcomes dogs, and has wheelchair-accessible entrances and parking, and its concession stand sells firewood if you are staying the night. If you are renting a pontoon from Big Papa's, note that it closes at 5 p.m. on Fridays, earlier than the rest of the week, so a Friday rental is a daytime plan.
For groceries and gas, plan to stock up in Friendship or neighboring Adams on the way out, since the shore roads around the park are mostly homes, campgrounds and a few bars.
Fishing
Castle Rock is a productive fishing lake because the old river channels and flooded ground under the surface give fish structure to hold on all year.
Walleye are the headline, and the lake hosts qualifiers for the Whiskey River Walleye Challenge out of Arkdale. The fish cleaning station at Castle Rock Park saves a mess back at the cabin. You will need a Wisconsin fishing license, and because the lake is a flowage, water levels are managed by the dam rather than the weather alone.
Lake Petenwell, upstream, is the bigger lake and has its own following among anglers. Since you cannot boat between them, pick one lake for the day and trailer to the other if you want both.
Eating on the east shore
The east shore's waterfront food runs along the roads north of Castle Rock Park: a Mexican place on the water, a bar and grill with Polish cooking, and a couple of lakeside taverns.
Dellwood Pavilion, 3.2 miles north of the park, is the place for Polish sausage and pierogies, plus a fish fry. It keeps short hours, opening at 4:30 p.m. Thursday through Sunday only, so check before you drive over.
Closer to the park, Rustic Ridge is a supper-club style restaurant on the water 1.7 miles north, with prime rib, a salad bar, a deck, boat docks, a Friday fish fry and Sunday fried chicken. The Slip Inn, under a mile north, is a walk-up lakeside bar that pours Old Fashioneds and makes pizza until late.
On the drive between the lake and the village, Spot in the Woods opens at 8 a.m. every day for breakfast and turns into a pizza, fish fry and Bloody Mary stop later on.
Back in the village, the Friday fish fry moves to Main Street’s bars and diners, about seven miles northeast of the park.
Camping and places to stay on this side
The east shore's main campground is Castle Rock Park itself, and for a cabin or a room you are looking at the village, the inn on WIS-13 or a rented lake house.
Inland, Roche-A-Cri’s 41 rustic sites sit in oak and pine woods 9 miles northeast of the park, a quieter choice if you want the mound and the rock art on your doorstep.
For a roof, the lakeside cabins at Friendship Island Resort come furnished, with a private sand beach, but be clear that they are on Friendship Lake in the village, not on Castle Rock.
Inn of the Pines on WIS-13 has 23 rooms, including jacuzzi suites. Vacation rental sites list several lake houses on the Castle Rock side, and the Castle Rock Lake Motel, Mobile Home and RV Park on County Highway Z takes RVs right on the water.
Across the water: Buckhorn and the west shore
Straight across the lake from the Adams County shore is Buckhorn State Park, a 4,500-acre park and wildlife area on a peninsula on the Juneau County side, established in 1971. It is worth the drive around if you have a second day.
Buckhorn's mix of floodplain forest, prairie, savanna and dry sand country is why so much lives there. In the marshes and sloughs you can see Canada geese, herons, sandhill cranes, muskrats, beavers and otters, and the uplands hold deer, wild turkeys and the occasional black bear. The park has a beach, a playground and miles of hiking and biking trails.
Off Buckhorn's southeastern shore is a small island locals call Alcatraz, where boats tie up together on summer afternoons and, when the timing is right, there is floating live music. If you rent a pontoon on this side of the lake, that is the usual destination.
Farther west, beyond the lake, Necedah is the town for the Necedah National Wildlife Refuge, established in 1939 in what was the Great Central Wisconsin Swamp. Its 43,656 acres are home to whooping cranes and trumpeter swans, and it is one of the best birding trips within reach of Friendship.
The history under the water
When the dam closed in 1951, the rising water covered farmland, prairie and wooded knolls along the old river, and two lumber towns with them, Germantown and Werner.
Germantown sat at the mouth of the Yellow River and dated to 1848. At its liveliest it had two breweries, and most of its buildings were moved before the water came up. Werner was mostly abandoned by the time construction started.
Go back far enough and the whole basin was the bed of Glacial Lake Wisconsin. Roche-A-Cri, 9 miles northeast of the park, was an island in that lake, which is why its cliffs rise so suddenly out of flat ground.
Seasons on the lake
Summer is boating season, and the lake is at its busiest on hot weekends. Fall is quieter, with the leaves turning around the shoreline, and LakeLubbers describes the reflected color as a patchwork quilt.
Winter does not close the east shore. Castle Rock Park is a designated snowmobile unload and load area and stays open year-round. On the Juneau side, the county park pulls its docks in November and puts them back in March, which tells you when the open-water season really starts. The numbers in Friendship’s month-by-month weather apply here too.
Away from the water, the Castle Rock horse trails run south of WIS-21 and east of 20th Avenue all the way down to where the Wisconsin River opens into the lake. They are not only for riders, and the public land around them, including the Solberg Silver Lake State Natural Area, is open to hunting in season.
From the lake back to Friendship
Castle Rock Park is 7.5 miles southwest of Friendship's village center, and Roche-A-Cri is 2 miles north of the village, so a lake morning and a stairway climb fit in the same day.
Between the lake and the mound, the rest of Friendship is a short list: a beach by the dam, a 9-hole golf course and the county fair in August.
Frequently asked questions
Published September 7, 2026
