The El Cielo Biosphere Reserve (Reserva de la Biosfera El Cielo in Spanish) is located in the Sierra Madre Oriental in the southern part of the Mexican state of Tamaulipas near the town of Gómez Farias. The reserve protects the northernmost extension of tropical forest and cloud forest in Mexico. It has an area of 144,530 hectares (357,100 acres; 558.0 sq mi) made up mostly of steep mountains rising from about 200 metres (660 ft) to a maximum altitude of more than 2,300 metres (7,500 ft).