Denison Dam, Embankment dam across Bryan County, Oklahoma and Grayson County, Texas, United States.

Denison Dam is an earthen embankment dam built across the Red River on the border between Oklahoma and Texas, forming Lake Texoma. The dam is roughly a mile (1.6 km) long and is one of the largest earthen dams in the United States, built for flood control and power generation.

Completed in 1943 primarily as a flood control project, Denison Dam was then the largest rolled-earth fill dam in the world, holding 18.8 million cubic yards of fill. General Lucius D. Clay managed the project, and German prisoners of war from Rommel's Afrika Korps cleared trees and lined drainage ditches during construction. It takes its name from Denison, Texas, downriver from the dam face.

The dam sits on the state line between Oklahoma and Texas, and visitors can walk across it and stand in two states at once. The lake it created, Lake Texoma, draws people from both sides of the border for fishing and outdoor recreation.

The dam is accessible by road and sits between the city of Denison, Texas and the Oklahoma side of Lake Texoma, making a car the easiest way to get there. Several parks and recreation areas surround the lake on both sides, so it is worth planning for at least half a day.

During the final years of construction, prisoners of war from North Africa were brought in to work on the site, an unusual detail for an American infrastructure project of that era. Their presence connected a remote corner of the American South directly to the wider events of World War II.