Lake Estes, formed by Olympus Dam, is located just east of downtown Estes Park. The lake plays an important role in the Colorado-Big Thompson (C-BT) Project power system. Lake Estes acts as an afterbay for the Estes Power Plant, and as a forebay to control the flow of water into the Olympus Siphon on its way to the Pole Hill Power Plant.
Construction of Lake Estes and Olympus Dam began in the summer of 1947, and the lake began filling in November 1948. Construction of the lake and dam cost $2.4 million.
Lake Estes has a capacity of 3,068 acre-feet, 185 surface acres, 5 miles of shoreline and a maximum depth of 45 feet.