Big Bend National Park covers more than 800,000 acres in southwest Texas. For more than 1,000 miles, the Rio Grande forms the international border between Mexico and the United States; Big Bend National Park administers roughly one-quarter of that boundary. Within the 118 twisting miles that also define the park’s southern frontier, the river’s south-easterly flow changes suddenly to the northeast and forms the “big bend” of the Rio Grande. Big Bend National Park has national connotation as the largest sheltered area of Chihuahuan Desert topography and ecology in the United States. Few areas surpass the park’s value for the fortification and study of geologic and paleontological resources. Archaeologists have discovered artefacts approximate to be 9,000 years old, and historic.