Granby Dam, Embankment dam in Grand County, Colorado, US.

Granby Dam is a 298-foot-tall earthfill dam on the Colorado River, 5.5 miles northeast of Granby in Grand County, Colorado. Completed in 1950, it impounds Lake Granby, the largest reservoir of the Colorado-Big Thompson Project, with a drainage area of 311 square miles.

Work on the dam started in 1941 as part of the Colorado-Big Thompson Project, a federal effort to move water from the western to the eastern side of the Rocky Mountains. The dam was completed in 1950 and became a central piece of that water transfer system.

The reservoir created by the dam is known as Lake Granby and draws visitors who come to fish, boat, and spend time near the water in the Rockies. On summer weekends, the lake feels busy with families and outdoor enthusiasts from nearby towns.

Lake Granby is open to visitors and offers fishing and boating during the warmer months, though temperatures can drop sharply even in summer at this elevation. Water levels change throughout the year, so the shoreline may look very different depending on when you visit.

The Granby Pumping Plant lifts Lake Granby water 125 feet (38 m) into the Granby Pump Canal, which runs 1.8 miles (2.9 km) to Shadow Mountain Lake; from there it passes through the Alva B. Adams Tunnel under the Continental Divide. Separately, water from Willow Creek just below the dam is pumped 175 feet (53 m) up into Lake Granby. The dam itself generates no power.