Boquillas Canyon is one of two famous gorges of the Rio Grande in Big Bend National Park. As with the other, Santa Elena Canyon, the meandering river suddenly cuts into steep limestone walls where a large mesa rises from the desert landscape. The dramatic geology is almost unbelievable, but information on signs near the trailhead help explain its formation. Also like Santa Elena, the canyon is located half in the United States and half in Mexico, with the middle of the river marking the international boundary. Unique to Big Boquillas, though, is easy access to the river banks on both sides. At Santa Elena Canyon there are steep cliff walls on the Mexico side. The town of Boquillas is just across from Big Boquillas Trailhead, and you can even cross the boundary with a valid passport to explore part of Mexico. Merchants from Mexico cross the river on most days and sell handmade souvenirs along the trail or sing songs for passing hikers. This makes the Big Boquillas hike an interesting cultural experience as well.
You will get nice views into Mexico across the river from a high bluff that the trail climbs over. On top you can also find evidence of ancient inhabitants who lived here. They left holes in the limestone underfoot that may have been used for grinding flour. The trail then descends the other side of the bluff and enters the mouth of the canyon, where there are sandy dunes, soggy wetlands, and shady groves, all beneath the towering stone walls. At less than a mile from the trailhead, the path dead ends where the shoreline runs out, and vertical rock descends to the water. The only way to continue would be by boat, so you must turn around the way you came.