Celaya is a city and its surrounding municipality in the state of Guanajuato, Mexico, located in the southeast quadrant of the state. It is the third most populous city in the state, with a 2005 census population of 310,413. The municipality for which the city serves as municipal seat, had a population of 415,869. The city is located in the geographic center of the municipality, which has an areal extent of 553.18 km² (213.58 sq mi) and includes many smaller outlying communities, the largest of which are San Miguel Octopan, Rincón de Tamayo and San Juan de la Vega.
There are many smaller towns around Celaya including Rincón De Tamayo, Tarimoro, Salvatierra, La Moncada, Panales Jamaica (Cañones), Panales Galera, La Calera, La Estancia, La Noria, La Acebuche, Cacalote, and Charco Largo.
An explosion in an improperly protected gunpowder and fireworks warehouse in September, 1999, killed over 60 people and badly injured over 300 
Celaya is also famous for the production of cajeta.
The Celaya Airport has as of January 22 2007 flights in and out, opening the city to tourism.
He is the father of popular Mexican soap opera actress Kate del Castillo. He has played in numerous telenovelas (soap operas) for the Mexican television, his most notable performances being in La Mentira along with his daughter Kate and Niña amada mía. He has also participated in many movies, of which the most known is El Ángel exterminador by Luis Buñuel (1962).