The Southern Pacific dry forests occupy the coastal lowlands and foothills along the Pacific coast of Southern Mexico. The Balsas River marks the western boundary of the ecoregion. The ecoregion extends inland to include the Oaxaca Valley. The ecoregion ranges from sea level to 1400 meters elevation. Higher-elevation areas of the northern mountains, including the Sierra Madre del Sur, Sierra Madre de Oaxaca, and the Sierra Madre de Chiapas, are home to montane pine-oak forests and moist forests.
^ abEric Dinerstein, David Olson, et al. (2017). An Ecoregion-Based Approach to Protecting Half the Terrestrial Realm, BioScience, Volume 67, Issue 6, June 2017, Pages 534–545; Supplemental material 2 table S1b. [1]