Built to provide irrigation water storage, flood control, and hydropower generation, it is the largest dam along the international boundary reach of the Rio Grande.

[1] The dam is over 6 miles (9.7 km) long, lies mostly on the Mexican side of the border, and forms Amistad Reservoir.

[3] When the reservoir filled, it inundated ancient rock art left by Native Americans who once lived in the areas.

[9] More than 170 archaeological sites were cataloged during salvage operations between 1958 and 1969, a difficult undertaking due to the arid and remote conditions of the area.

[11] Of the dam's roughly US$125 million cost, the US paid about 57% and Mexico 43%, in accordance with the division of water storage rights in the reservoir.

The center section at the Rio Grande is a concrete gravity dam 2,182 feet (665 m) long, with the remainder being earthen embankment.

The IBWC determines the fraction of water stored in Amistad Reservoir belonging to either country on a biweekly basis, based on this allocation.

[17] The reservoir levels fluctuate greatly due to the region's highly variable annual precipitation as well as heavy water use.

[20] Although the majority – about 70% – of the inflows to Amistad Reservoir comes from the Rio Grande, Devils, and Pecos Rivers, about 30% is from local springs.

Inflows typically peak between August and October due to monsoon storms and hurricanes that strike the Gulf Coast.

Flood flows caused by hurricanes are short-lived, but can be extreme,[21] with a maximum (since dam construction) of more than 800,000 cubic feet per second (23,000 m3/s) in late September, 1974.

The Dam was a bi-national effort to establish flood control on the Rio Grande and provide sources of water.

Although US Department of Transportation statistics combine traffic counts with Del Rio Texas Port of Entry, approximately 65,000 vehicles crossed the dam into the US in 2005.