Mexico is a first-class municipality belonging to the third district of the Province of Pampanga. It has a total land area of 11,761 hectares and a recorded population of 141,298 in 2007.

The municipality has 43 barangays with flat slopes ranging from 0 to 3 percent. It is bounded in the North by the municipality of Magalang; in the South by the municipality of San Luis; in the East by the municipalities of Arayat and Sta. Ana; and in the West by the cities of Angeles and San Fernando.

The municipality of Mexico shares similar physical and cultural features with the City of San Fernando. Its proximity to the said city places Mexico in an advantage location as catch area for San Fernando’s economic spillover. This is evident on the growing numbers of commercial establishments in the western part of the municipality.