Santa Elena Canyon, on the Rio Grande in southwestern Brewster County, is one of the most famous canyons in Big Bend National Park. It separates the limestone mesas of the Mesa de Anguila on the northern or Texas side of the river from the Sierra Ponce on the southern or Mexican side. The entrance of the seven-mile canyon is located seven miles southeast of Lajitas (at 29°11' N, 103°42' W). Its mouth is located six miles northwest of Castolon at the southeastern end of the Mesa de Anguila (at 29°10' N, 103°37' W). Santa Elena Canyon, like Mariscal and Boquillas canyons, was carved out of thick layers of limestone originally deposited as sediments in the shallow sea that covered the Big Bend between sixty million and 130 million years ago. A mile below the entrance to the canyon, a rockslide from the Mexican side, known as the Labyrinth, rises to a height of 180 feet above the river and constitutes a major navigational hazard for boaters. Below the rockslide the canyon is narrow (sometimes as narrow as twenty-five feet) and sheer. Its walls reach a height of 1,500 feet above the river.
These aspects of Santa Elena Canyon, which are the source of its unique beauty, also made it a fearsome obstacle to early explorers. In 1747 Governor Pedro de Rábago y Terán of Coahuila led an expedition into the Big Bend. He tried to follow the Rio Grande on the Texas side, but had to go around the canyon. About 1850 Capt. John Love led an expedition from Ringgold Barracks in Starr County up the Rio Grande to "Babbitt's Falls," the exact location of which is unknown but may have been in Santa Elena Canyon. In August 1852 M. T. W. Chandler led an expedition charged with surveying the Rio Grande from El Paso to the mouth of the Pecos River. At the mouth of Santa Elena Canyon, Chandler stopped and climbed the Mesa de Anguila to assess the party's chances of surviving a trip through the canyon. He decided to detour around Santa Elena Canyon, as did Lt. Duff C. Green, in charge of the Chandler party's supply train. In the summer of 1860 an expedition of camels from Fort Davis under Lt. William Echols followed the Rio Grande from Lajitas to the mouth of the canyon, which he called the Grand Puerta, then detoured northeast to Terlingua Creek and back down to the Rio Grande just below the canyon. In 1881 a party including John T. Gano, the son of a Confederate general and deputy surveyor of Presidio County, floated down the Rio Grande and through Santa Elena Canyon. Several years later Gano, the founder of the G4 Ranch, established a line camp just downstream from the canyon. Not until October 1899, however, did Robert T. Hill undertake the first scientific exploration of the canyon. One of the best-known trips through Santa Elena Canyon was undertaken in May 1937 by historian Walter Prescott Webb, who was appointed a consultant to the National Park Service during the effort to establish Big Bend National Park and who wanted to call attention to the scenic beauties of the area. In more recent years, and especially since the opening of the park in 1944, the canyon has become a popular recreational spot.