Horsetooth Reservoir

Horsetooth Reservoir is a man-made body of water in Larimer County, Colorado, stretching roughly six miles between two parallel ridges. Along the eastern shore, red-brown sandstone cliffs rise sharply, giving the waterline a distinct outline.

The Bureau of Reclamation built four earthen dams starting in 1949 as part of the Colorado-Big Thompson Project to supply water. The work created a large storage facility that channels water from the western slope of the Rockies to farmland east of the mountains.

The name comes from a rock formation that resembles a horse's tooth when seen from a distance, still visible today along the shore. Sailboats glide past motorboats while anglers settle into small coves and divers explore the deeper sections of the water.

Visitors need an entrance permit for the area and a separate permit if they plan to stay overnight at one of the campgrounds. Camping stays are limited to fourteen nights within any thirty-day window.

The water reaches depths of roughly two hundred feet (about sixty meters) in some areas, offering divers unusually clear visibility in the deeper zones. The elevation at about 5400 feet (1650 meters) affects water pressure during dives and requires adjusted calculations for dive time.

Location: Larimer County

GPS coordinates: 40.55436,-105.15591

Latest update: December 5, 2025 22:27