Glendora, city, Los Angeles County, southwestern California, at the foot of the San Gabriel Mountains; incorporated as a city 1911. Irrigation systems, pumps, dental equipment, and strawberries are produced in the city. A community college is here. A ranch was established here in 1844 but permanent settlement did not begin until 1874. The community was a citrus-growing center until large-scale residential growth began in the late 1940s. The city's name is derived from “glen” and “Leadora,” the name of the wife of a land developer (1880s) here. Population 38,654 (1980); 47,828 (1990); 49,415 (2000).