Eagle Nest Dam, Arch dam in Colfax County, New Mexico.

Eagle Nest Dam is a 140-foot-high arch dam on the Cimarron River east of Eagle Nest, New Mexico. Its crest is 400 feet long and 9.5 feet wide, widening to 45.2 feet at the base between two granite walls. The dam impounds Eagle Nest Lake, a 2,500-acre reservoir 5 miles long and 2 miles wide.

The dam was built between 1916 and 1918 by Taos Pueblo workers and resulted from an initiative by Frank and Charles Springer through their land company. The project emerged to store water for irrigation and marked an important phase in the region's water development.

The dam takes its name from eagles that nested on its granite sides. Taos Pueblo laborers built the structure between 1916 and 1918. Water rights sold by Frank Springer to finance the work became known as vested rights, and the 2006 Eagle Nest Water Rights Settlement still governs how users share shortages, prorated by the lake level on June 1.

The dam stands on private property just east of Eagle Nest, reached via U.S. Route 64; the structure itself is not open to visitors, so the lake is seen from public areas of Eagle Nest Lake State Park. The lake surface sits at 8,172 feet (2,491 m) when full, and the dam lies between two granite walls.

The dam was for many years the largest privately initiated project of its kind in the United States and set new standards in water engineering. The water distribution system relies on innovative legal procedures governing usage rights among different users.