Shadow Mountain Lake is a reservoir in Grand County, Colorado, near the headwaters of the Colorado River. Shadow Mountain Lake is created by Shadow Mountain Dam. The lake forms a continuous body of water with Grand Lake, the largest natural lake in Colorado; they are separated by gates.

Shadow Mountain Lake
Shadow Mountain Lake looking West
Shadow Mountain Lake Show map of Colorado Shadow Mountain Lake Show map of the United States
Location	Grand County, Colorado, United States
Coordinates	40°13′40″N 105°50′35″W / 40.22778°N 105.84306°W / 40.22778; -105.84306
Basin countries	United States
Surface area	1,346 acres (545 ha)
Water volume	16,848 acre-feet (20.782×10^6 m3)
Surface elevation	2,550 m (8,366 ft)
Settlements	Grand Lake

Shadow Mountain Lake is part of Arapaho National Recreation Area.

The creation of Shadow Mountain Lake was authorized by the Colorado-Big Thompson bill, passed in 1937,^[1] which also created the Colorado-Big Thompson Project. Water from the Grand Lake-Shadow Mountain Lake body is diverted through the Alva B. Adams tunnel, at the eastern edge of Grand Lake, into the Big Thompson River on the east side of the Continental Divide. Storage began in 1947.