Anchor Dam, Arch dam in Hot Springs County, Wyoming, US

Anchor Dam is an arch dam in Wyoming that creates a reservoir for storing water. The structure spans across the valley and holds water primarily for agricultural irrigation throughout the region.

The dam was built in the 1960s as part of a larger water development project for the region. It was designed to address growing water needs for farming communities in the area.

Anchor Reservoir is operated by the local Owl Creek Irrigation District, which releases its stored water so that ranchers can irrigate hay and pasture through July and August of each season. Because the reservoir has never filled to its design capacity, that late-summer supply is limited.

The location is accessible by local roads and offers nearby camping and hiking opportunities. The best time to visit is spring or fall when temperatures are more comfortable.

Bureau of Reclamation scientists knew before and during construction that the site lacked "hydraulic integrity", yet the dam went ahead. More than 50 sinkholes have been mapped in the Chugwater Formation beneath the basin, one of them 30 feet across and 35 feet deep. The reservoir has never filled to its 17,400 acre-foot design capacity.