Sierra Madre (known in Mexico as Sierra Madre de Chiapas) is a mountain range (located at ) which runs northwest-southeast from the state of Chiapas in Mexico across Guatemala and into El Salvador and Honduras. Most of the volcanoes of Guatemala are a part of this range.
A narrow coastal plain lies south the range, between the Sierra Madre and the Pacific Ocean. To the north lie a series of highlands and depressions, including the Chiapas Depression, which separates the Sierra Madre from the Chiapas Plateau, the Guatemalan Highlands, and Honduras' interior highlands.
It is known near Guatemala city as the Sierra de las Nubes, and enters Mexico as the Sierra de Istatan. Its summit is not a well-defined crest, but is often rounded or flattened into a table-land. The direction of the great volcanic cones, which rise in an irregular line above it, is not identical with the main axis of the Sierra itself, except near the Mexican frontier, but has a more southerly trend, especially towards El Salvador; here the base of many of the igneous peaks rests among the southern foothills of the range. It is, however, impossible to subdivide the Sierra Madre into a northern and a volcanic chain; for the volcanoes are isolated by stretches of comparatively low country; at least thirteen considerable streams flow down between them, from the main watershed to the sea. Viewed from the coast, the volcanic cones seem to rise directly from the central heights of the Sierra Madre, above which they tower; but in reality their bases are, as a rule, farther south. East of Volcán Tacana (4,092 meters) which marks the Mexican frontier, the principal volcanoes are Tajumulco (4,220 meters); Santa Maria (3,777 meters), which was in eruption during 1902, after centuries of quiescence, in which its slopes had been overgrown by dense forests; Atitlan (3,557 meters), overlooking Lake Atitlan; Acatenango (3,975 meters); Fuego (i.e. "fire," 3,763 meters), which received its name from its activity at the time of the Spanish conquest; Agua (i.e. "water," 3,765 meters), so named in 1541 because it destroyed the former capital of Guatemala with a deluge of water from its flooded crater; and Pacaya (2,550 meters), a group of igneous peaks which were in eruption in 1870. East of the Guatemalan border, the range forms the boundary between El Salvador and Honduras. In El Salvador, the volcanoes form a line well south of the range, where over twenty volcanoes form five clusters. Between the Sierra Madre and the Volcanic line lies a central plateau.
The Sierra forms the main watershed between the Pacific and Atlantic river systems. On the Pacific side of the Sierra the distance to the sea is short, and the streams, while very numerous, are consequently small and rapid. A few of the streams of the Pacific slope actually rise in the Guatemalan Highlands, and force a way through the Sierra Madre at the bottom of deep ravines. On the eastern side a number of the rivers attain a very considerable development.