The rolling mesquite and acacia brushlands of this park are located on 26,000-acre Choke Canyon Reservoir, a water supply for Corpus Christi, and are found in two units: The Calliham Unit, containing 1100 acres, in McMullen County, and the South Shore Unit, which contains 385 acres in Live Oak County. Choke Canyon Reservoir has been recognized as a place of special importance for birds and bird watchers by a joint project of the American Birding Association and the Bureau of Reclamation. Large numbers and varieties of birds are attracted to the water and to the adjacent upland habitats; also, many typically Mexican species of birds approach the northern limits of their range here, making this one of Texas' finest places to watch birds. Choke Canyon is the westernmost common occurrence of the American alligator. Rio Grande turkey, whitetail deer, javelina, and coyote are among the most common animals. The crested caracara (Mexican eagle) can also be seen in the area. Both Calliham and South Shore offer camping, picnicking, boating, hiking, wildlife viewing, birding, fishing, lake beach and pool (during summer months) swimming, and softball and volleyball areas.

• Ride horseback in the North Shore primitive area lands accessible from the South Shore park unit.
• Launch your boat and try your hand at catching largemouth bass, white bass, striped bass, white crappie, bluegill, longear sunfish, green sunfish, flathead, channel and blue catfish, carp, freshwater drum, and gar.
• Learn about the inhabitants of the local ecosystem at the wildlife educational center located in the Calliham Unit.