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. Its mouth is located six miles northwest of Castolon at the southeastern end of the Mesa de Anguila. 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.
This is an aerial view of Santa Elena Canyon in Big Bend National Park. Mexico is on the left side of the canyon, US on right and mountains in background are Mexico. The canyon is the crack in the rock.