San Antonio de la Cal is a town and municipality in Oaxaca in southeastern Mexico and is the fifth most densely populated municipality in Oaxaca; only four Oaxacan municipalities are more densely populated than it: Oaxaca, San Jacinto Amilpas, Santa LucÃÂa del Camino, and Santa Cruz Amilpas. The municipality covers an area of 11 km<sup>2</sup>. It is part of the Centro District in the Valles Centrales region. As of 2005, the municipality had a total population of 15,071.