Otumba is a municipality located in the State of Mexico within the country of Mexico. The municipal seat and largest town of the region is Otumba de Gómez Farías.
The municipality covers a land area of approximately 143.42 square kilometres (55 mi2). According to the 2005 intermedial census, known as the Conteo de Población y Vivienda, the population was recorded at 29,873.