San Martín Atexcal

San Martín Atexcal is the seat of the municipality of Atexcal in southern Puebla, in the Tehuacán region. The name comes from the Nahuatl atl, water, and texcalli, rock: "water springing from the rocks". The village stands at about 1,800 m and had 977 people in 2020. The municipality, about 395 km², is one of the largest in the state and borders Juan N. Méndez, Tehuacán, Zapotitlán, Oaxaca, Totoltepec de Guerrero and Coyotepec.

Its relief has three parts: to the west, the eastern end of the Sierra de Acatlán, with Cerro de la Pila and the Cordón de la Culebra; in the middle, the broad, flat Acatlán valley; and to the east, the Sierra de Zapotitlán, with the highest summits, Cerro Texcal and Cerro Gordo, over 2,500 m.

Atexcal is well known to palaeontologists. On the Magdalena River, in Albian rocks of the San Juan Raya formation from the Early Cretaceous, dinosaur tracks appear on six levels through 9 m of rock: theropod and ornithopod footprints on the lowest level and sauropod tracks on the middle ones. It is one of the few Early Cretaceous sites in Mexico with recorded footprints. After the 2025 rains, INAH confirmed new tracks of plant- and meat-eating dinosaurs about 120 million years old at sites in Atexcal and Tehuacán.