Celaya (sāläˈyä) [key], city (1990 pop. 214,856), Guanajuato state, W central Mexico. In a region watered by the Lerma irrigation works, Celaya is the center of a prosperous corn, cereal, and bean growing area. Cattle raising and the associated dairy industry are also important. Founded in 1571, Celaya was frequently involved in Mexican wars. It was the first city to be captured (Sept. 28, 1810) by Hidalgo y Costilla. In 1915, Álvaro Obregón decisively defeated Francisco Villa at Celaya.