Montgomery Reservoir, reservoir in Park County, Colorado, United States

Montgomery Reservoir is a manmade lake built in 1957 by Colorado Springs, sitting at over 10,800 feet in elevation near Hoosier Pass. The water is contained by an asphalt-lined dam measuring over 1,900 feet long and more than 100 feet high, designed to withstand harsh mountain weather.

Montgomery Dam and Reservoir were completed in 1957 by Colorado Springs Utilities to store water for the city. The site lies near Hoosier Pass in the Mosquito Range, where mining had shaped the landscape for decades before the valley was flooded. The dam is a rockfill structure 1,900 feet long and 113 feet high, sealed with an asphalt concrete facing.

The reservoir takes its name from the Montgomery family, early settlers in the Blue River valley whose ranch land was among those flooded when the dam was built. The surrounding Mosquito Range still holds traces of the mining era that preceded the reservoir, and the site is now used by anglers and hikers passing over Hoosier Pass.

The reservoir sits at 10,873 feet (3,314 m) near Hoosier Pass, a few miles north of Alma; the access road climbs steeply and snow can close it in winter. Colorado Springs Utilities owns the site, so facilities are minimal and the altitude demands slow pacing. The dam is a rockfill structure about 1,900 feet long and 113 feet high, sealed with an asphalt concrete facing.

Most of the reservoir's water does not come from the small 7.7-square-mile basin above the dam but through the Hoosier Tunnel, which collects Blue River water west of the Continental Divide. The lake drains into the 70-mile Blue River Pipeline, which runs by gravity to the North and South Catamount reservoirs on Pikes Peak before treatment for Colorado Springs.