The Sumidero Canyon is a spectacular fissure in the earth, found north of Tuxtla Gutiérrez. In 1981, the Chicoasén hydroelectric dam was completed at its northern end, damming the Río Grijalva, which flows through the canyon, and creating a 25km-long reservoir. Traveling between Tuxtla and Chiapa de Corzo, the road crosses the Grijalva just south of the canyon mouth.
The most impressive way to see the canyon is from a lancha that speeds between the canyon’s towering rock walls. It’s about a two-hour return trip, starting at either Chiapa de Corzo or the Embarcadero Cahuaré, 5km north of Chiapa along the road to Tuxtla. You’ll rarely have to wait more than half an hour for a boat to fill up. Bring a drink, something to shield you from the sun and, if there’s any chance of bad weather, some warm clothing or a waterproof jacket.
It’s about 35km from Chiapa de Corzo to the dam. Soon after you pass under Hwy 190, the canyon walls tower an amazing 800m above you. Along the way you’ll see a variety of birds – herons, cormorants, vultures and kingfishers – plus probably a crocodile or two. The boat operators will point out a few odd formations of rock and vegetation, including one cliff face covered in thick hanging moss, resembling a giant Christmas tree. Disappointingly, the lanchas sometimes have to plow through floating plastic garbage when wet-season rains wash in trash from Tuxtla Gutiérrez.