Amatán Municipality is a municipality in the Mexican state of Chiapas, in southern Mexico. It covers an area of 109.3 km². As of 2010, the mun…Amatán Municipality is a municipality in the Mexican state of Chiapas, in southern Mexico. It covers an area of 109.3 km². As of 2010, the municipality had a total population of 21,275, up from 18,775 as of 2005.