In 1814, a visitor Manuel Gómez, founded a new settlement called Ashlumal into which many indigenous families moved into and the area became known as San Carlos.

[3] In 1848 by national decree, Comitán established a centre of commercialization in San Carlos and reclaimed land from salt marsh along the river for exploitation.

On July 20, 1942, by disposition of the governor Rafael Pascacio Gamboa, the town and surrounding area became an official second class municipality of Chiapas.

[2] Altamirano borders Ocosingo to the north, Las Margaritas to the south, and Chanal and Oxchuc to the west.

[1] Other than the town of Altamirano, the municipality had 189 localities, the largest of which (with 2010 populations in parentheses) were: La Laguna (1,222) and Morelia (Victórico Rodolfo Grajales) (1,156), classified as rural.