San Mateo is a canton in the Alajuela province of Costa Rica. The head city is in San Mateo district.
San Mateo was created on 7 August 1868 by decree 30.
San Mateo has an area of and a mean elevation of metres.
The northern border of the elongated province is formed by the Jesús MarÃÂa, Machuca, Agua AgrÃÂa, Calera rivers and Quebrada Zapote. The Quebrada Concepción, Grande de Tárcoles and the Machuca rivers establish the southern border. Cerro La Lana is a landmark that delineates a northeast tip of the canton.
The canton of San Mateo is subdivided into the following districts:
For the 2011 census, San Mateo had a population of inhabitants.
The canton is covered by the following road routes: