The Southern Sierra Madre, also known as the Sierra Madre del Sur is the southernmost mountainous region in Mexico and is located near to the Pacific coast in south Mexico. This range extends about 620 miles from southern Michoacán eastward through Guerrero to the Isthmus of Tehuantepec in eastern Oaxaca.

The Sierra Madre del Sur joins with the Transcontinental Volcanic range of central Mexico in northern Oaxaca, but is separated from this range further west by the valley of the Río Balsas and its tributary the Río Tepalcatepec.

The highest elevation in this range is in southern Oaxaca, called Cerro Nube at 12,200 feet.

Intrigral with the Sierra Madre system and part of the American Cordillera, the Sierra Madre del Sur is a mountain range in southern Mexico, extending about 620 miles from southern Michoacán east through Guerrero, to the Isthmus of Tehuantepec in eastern Oaxaca.

The Sierra Madre del Sur joins with the Transcontential Volcanic Mountain to the north in northern Oaxaca but is separated from this range in the west by the valley of the Río Balsas and its tributary the Río Tepalcatepec.