Big Bend National Park is a national park located in the U.S. state of Texas. Big Bend has national significance as the largest protected area of Chihuahuan Desert topography and ecology in the United States, which includes more than 1,200 species of plants, more than 450 species of birds, 56 species of reptiles, and 75 species of mammals.
The park covers 801,163 acres (1,252 sq mi; 3,242 km2). Few areas exceed the park's value for the protection and study of geologic and paleontologic resources. A variety of Cretaceous and Tertiary fossil organisms exist in abundance. Archaeologists have discovered artifacts estimated to be 9,000 years old, and historic buildings and landscapes offer graphic illustration of life along the international border in the 19th century.
For more than 1,000 miles (1,600 km), the Rio Grande/Río Bravo forms the international boundary between Mexico and the United States, and Big Bend National Park administers approximately 244 miles (393 km) along that boundary. The park was named after the area, which is bounded by a large bend in the Texas-Mexico border (see map at right below).
Because the Rio Grande serves as an international boundary, the park faces unusual constraints when administering and enforcing park rules, regulations, and policies. In accordance with the Treaty of Guadalupe Hidalgo, the park has jurisdiction only to the center of the deepest river channel as the river flowed in 1848. The rest of the land south of that channel, and the river, lies within Mexican territory.
