|Municipality created||27 November 1963|
|City status||6 December 1983|
|o Municipal President||Reynaldo Mora Nuñes (2008-10)|
|Elevation||260 m (850 ft)|
In the 2005 INEGI Census, the city reported a total population of 23,573.
The site had been a 10,000-acre (40 km2) area of rolling plains and hills used for cattle grazing (potreros). Hundreds of little asphalt springs dotted the area where cattle bones could be seen caught in the black seepage. Oil drilling in the area began in 1906.
The town's population grew exponentially following the drilling of the Cerro Azul No. 4 well, at the time the world's largest pumping 260,000 barrels per day (BPD), in February 1916. The well was drilled by Herbert Wylie for the Mexican Petroleum Company, then controlled by California oilman Edward L. Doheny. When the well came in the sound could be heard 16 miles (26 km) away in Casiano, and shot a stream of oil 598 feet (182 m) into the air, sending oil in a two-mile (3-km) radius. Over the next 14-years the well would produce over 57 millions barrels. Doheny formed the Pan American Petroleum and Transport Company, of which the Mexican Petroleum Company portion would later become the PEMEX.