Eleven Mile State Park, State park with reservoir in Lake George, Colorado, US

Eleven Mile State Park surrounds the 5.5-mile-long Eleven Mile Canyon Reservoir, held back by a 151-foot-high concrete arch dam completed in 1932. The dam's light tan-gray crest curves across the valley, with a small red-roofed building at its downstream base where water exits. A road with vehicles winds below the dam, and a rocky, pine-covered slope rises above the dark blue water on the right.

The dam controlling this reservoir was built in the 1930s as part of a major water project to supply Denver with drinking water. Its construction transformed the valley floor and permanently altered how water moved through the region.

The Kokanee salmon run draws anglers to the Dream Stream, the river current along the reservoir's north side. The reservoir is known for afternoon winds that shape how people fish and boat. The park lies within the South Park National Heritage Area.

The park has campgrounds and boat launches spread around the shoreline at different locations. Several trails allow visitors to walk various lengths, though arriving early is wise since popular spots fill up quickly on weekends.

The reservoir is fed by the South Platte River, and the stretch of current along its north side is known as the Dream Stream, noted for Kokanee salmon. Afternoons here are often windy. The dam is a concrete arch 151 feet high and 375 feet long, holding up to 128,000 acre-feet at an elevation of 8,567 feet.