Sontecomapan Lagoon (Laguna Sontecomapan also Laguna de Sontecomapan) occupies an alluvial plain in the center of the Sierra de Los Tuxtlas, 18°33′N 95°1′W / 18.550°N 95.017°W, in southeast central Veracruz, east central Mexico on the edge of the Gulf of Mexico. The laguna is part of the Catemaco municipio stretching from the Gulf of Mexico to the foothills of the San Martin Tuxtla Volcano and the Sierra Santa Marta. In 2004 RAMSAR (International Convention on Wetlands, signed in Ramsar, Iran 1971) added Laguna Sontecomapan to its list.