Guernsey State Park swimming beaches

The swimming beaches at Guernsey State Park are named plainly: Sandy Beach, Sandy Point, and Sandy Cove. Each is a campground first and a beach second, set along the shore of Guernsey Reservoir, the North Platte River held back behind Guernsey Dam a short way above the town of Guernsey. The state calls these three the park’s actual “beaches.” The entire reservoir is open to swimming, and its miles of shoreline give public access wherever a swimmer can reach the water. Pets are not allowed on the designated beaches, and no one may fish within 20 yards of them.

The park gives the swimming season as generally April through September, “as water levels allow,” and calls daylight the safest time to be in the water. In the 2026 season a harmful cyanobacterial bloom advisory went into effect on June 19. It told visitors to avoid contact with water near the bloom and not to swallow it, to keep clear of its spray, to rinse fish and eat only the fillet, and to keep pets and livestock from drinking nearby.

The reservoir lies in the hills of the Hartville Uplift. The National Historic Landmark nomination describes that formation as a transition between the high plains to the east and the Rocky Mountain foothills to the west. The ground is rocky and dry, but at 4,000 to 5,000 feet it gets enough moisture for scattered ponderosa pine, juniper, and cedar. The state park around the water covers some 6,000 acres. It holds 19 campgrounds and 250 campsites, each campground with a comfort station, picnic tables, and fire grills.

Water that comes and goes

The reservoir belongs to the Bureau of Reclamation’s North Platte River Project. Guernsey Dam stores water and also controls flow from other dams on the river, and Reclamation lowers the reservoir for an annual silt run. In 2017 the run was scheduled to begin on the evening of July 4. In 2021 the park announced that the reservoir would empty by late August. In 2023 it advised that recreation was still available despite the silt run, and in 2025 it posted a low water notice.

Electricity and a single bid

The dam began with a search for electricity. Eastern Wyoming residents first discussed a dam near Guernsey in 1915, and Congress authorized it in 1924. On May 2, 1925, the contract went to the Utah Construction Company of Salt Lake City, the only company to bid, and work began three weeks later. By summer 200 laborers were at the mouth of the small canyon, gathering broken rock with steam shovels. Trains hauled the rock to the site and dumped it from trestles on each side of the embankment.

The dam was completed on July 13, 1927. It is a 135-foot-high, diaphragm-type embankment of sluiced clay, sand, and gravel. The dam, its two-generator power plant, and its classical arch gatehouse are listed on the National Register of Historic Places. The reservoir first filled that year, on federal land Reclamation had bought for the project.

Under Reclamation, leased summer cabins went up along the lake between 1928 and 1934. Cabins still stand in that zone along Lakeshore Drive, most of them postwar construction. The lake lay within driving distance of Cheyenne, Scotts Bluff, and Fort Laramie, and local boosters pushed to develop it, expecting it to draw more tourists to the region.

Two companies on opposite shores

On May 21, 1934, the Civilian Conservation Corps set up Camp BR-9 on a bluff north of the dam. Camp BR-10 followed in July, about a mile west of the dam, when the shoreline was still largely undeveloped. According to the state’s Guernsey Museum Digitization Project, Company 844 at BR-9 built the facilities on the east side of the reservoir and Company 1855 at BR-10 built those on the west. The split was made intentionally to foster competition. The same source says that in this spirit even a latrine became a source of pride. The Million Dollar Biffy cost over $6,000 to build and was purported to be worth a million dollars, which is how it got its name.

The state’s account calls Guernsey the first cooperative venture of the Bureau of Reclamation, the National Park Service, and the CCC to develop a public recreation area. The National Park Service calls it one of the first two such joint projects. The state also says Guernsey was one of the first places CCC workers were allowed to do skilled labor. Until then the corps had been regarded as general laborers for forestry and soil conservation. CCC regional director Herbert Maier oversaw the architectural and site design at first. By the state’s account, the Park Service planners Conrad Wirth and Thomas Vint, credited with the Rustic architectural movement, honed their trade here.

The crews built the transportation network first. Lakeshore Drive gave access to the water. Skyline Drive, nicknamed the Mae West Road by the CCC boys, climbed over 400 feet in tight curves to the high bluff on the west side of the flooded canyon. Winding steps from Skyline Drive lead to the Castle, which has a giant fireplace and an observation area above the reservoir. Its lower level has two arched walkways, and when the two archways are lined up they point directly to Laramie Peak.

The museum stands on a high cliff over the water. It is built of locally quarried bluff and white sandstone under a roof of hand-hewn timbers and cedar shingles. Its flagstone floor was quarried, assembled, and numbered in Thermopolis, then taken apart, shipped to Guernsey, and put back together, and some of the numbers can still be seen. Inside, two exhibit halls and 14 display cases cover eastern Wyoming history and prehistory, essentially intact to 1937. Historian Christine Pfaff calls the park “the most important early example of recreational development around a Reclamation reservoir in the West.”

A float at the southeast corner

The landmark nomination says swimming, boating, and other active recreation have been the principal activities in the park since it was created, and motorboats were among the most popular from the earliest days. Along Lakeshore Drive, each parking area or stop was marked by a building, a picnic shelter, or a structure such as a swimming float or boat pier. The planners kept this development in the eastern bays. The larger western part of the reservoir was left undeveloped as a conservation zone, with the Castle on the dividing line between the two.

Richard G. Redell’s 1937 master plan called for more. Among his proposals was a stone bathhouse for swimmers near the popular swimming float at the southeast corner of the lake. Neither the bathhouse nor his other larger projects were built before the last CCC enrollees left the park in 1939.

The park came under state management in 1957. In 1980 it was placed on the National Register, one of the first CCC-era state parks recognized for its architecture. In 1997 the Lake Guernsey State Park District was designated a National Historic Landmark. The nomination calls it “an extremely significant and well preserved state park of the period.” In the early 1980s the state added Sandy Beach, which opened the western portion of the reservoir to direct access. It was sited well away from the CCC work, and the nomination counted it a relatively minor impact on the park’s integrity.