Dillon Reservoir, Reservoir in Summit County, Colorado, United States

Dillon Reservoir is a mountain reservoir in Summit County, Colorado, sitting between the towns of Dillon, Frisco, and Silverthorne. The water body covers 13 square kilometers (8 square miles) with a shoreline of 43 kilometers (27 miles).

Denver Water Board began buying land in the Blue River valley during the Great Depression, and in 1956 it told remaining residents to leave by September 15, 1961. Dam construction ran from 1961 to 1963, creating an earth-filled dam 5,888 feet long and 231 feet high. The town of Dillon moved to a 172-acre site on the Fred Phillips Ranch, and 327 graves were relocated to a new cemetery.

The lake draws sailors who meet regularly through a local yacht club that organizes races during warm months. These competitions bring together water sports enthusiasts from across the state and add life to the shoreline communities.

Between June and September, visitors can rent boats at marinas in Dillon or Frisco Bay, while fishing remains open year-round from shore or vessel. The lake sits above 2700 meters (9000 feet) elevation, so weather conditions can shift quickly and warm clothing is advisable even in summer.

Water flows through a tunnel beneath the Continental Divide, supplying Denver with 40 percent of its drinking water. This underground passage is named after a former water manager and ranks among the longest of its kind in the Rocky Mountains.