Dillon Reservoir Dillon Reservoir Dillon Reservoir, sometimes referred to as Lake Dillon, is a large fresh water reservoir located in Summit County, Colorado, south of I-70 and bordered by the towns of Frisco, Silverthorne, and Dillon. It is a reservoir for the city of Denver, and its waters are under the control of Denver Water. Popular ski areas are close to the reservoir, including Copper Mountain, Keystone, Arapahoe Basin, and Breckenridge. In 1859, a large party of gold-seekers led by Ruben Spalding discovered gold near the headwaters of the Blue River, which prompted a population surge in Summit County, Colorado. By October
Dillon Reservoir 1859, nearly 100 miners had camped along the river. By 1880, the human population of Summit county had swelled to 5,459. In 1881, Dillon Mining Company patented a 320-acre parcel and divided it into lots to establish the trade-post town of Dillon along the northeast bank of the Snake River, which is part of what was then called Blue River Valley. The town of Dillon was incorporated in 1883, but soon relocated to the west bank of the Blue River when Denver and Rio Grand Railroad came to Blue River Valley but had bypassed Dillon. Dillon was moved a second