Coordinates: 40°22′36″N 105°29′18″W / 40.37667°N 105.48833°W Lake Estes is a reservoir in Estes Park, Colorado. It is held up by Olympus Dam. The lake has a shoreline of about 4 miles and a surface area of 185 acres. The reservoir lies on the Big Thompson River and is a component of the Colorado-Big Thompson Project.