Choke Canyon State Park is on the shore of the Choke Canyon Reservoir, which supplies water for Corpus Christi.

Eroded, gently rolling brushland crossed by silted stream valleys makes up the terrain here. This land formed during the Cenozoic Era the period following the extinction of dinosaurs.

Ancient rivers flowing to the southeast dumped their sediments into what was then part of the Gulf of Mexico. This created new land.

Seas intermittently covered the newly-formed land with more river sediment. These sediments were mostly volcanic ash, claystone, siltstone, tuff, shale and shaley limestone.

Over time, erosion of these sediments and subsequent deposits of river silt produced the land you see today.

The Choke Canyon Dam is near where the Gulf shoreline was about 30 million years ago.

The state acquired the park in 1981 in a 50-year agreement between the Bureau of Reclamation, the city of Corpus Christi and the Nueces River Authority.

The Calliham Unit contains 1,100 acres in McMullen County. It opened on Aug. 21, 1987. The 385-acre South Shore Unit is in Live Oak County. It opened on March 5, 1986.

From the scant evidence available, we know that Paleo Indians crossed the Frio River Valley more than 10,000 years ago. They were following game such as bison and mammoth.

After large game disappeared more than 8,000 years ago, nomadic hunters and gatherers associated with the Archaic culture camped near the river. There they made tools, built fires, and gathered and processed food. Archeologists have found numerous Archaic sites in the Choke Canyon area.