Big Bend National Park is a national park located in the U.S. state of Texas. For more than 1,000 miles (1600 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.

Big Bend National Park 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 (3,242 km2). Few areas exceed the park's value for the protection and study of geologic and paleontologic resources. Cretaceous and Tertiary fossil organisms exist in variety and abundance. Archeologists 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 1800s.