Glendora, city (1990 pop. 47,828), Los Angeles co., S Calif., a growing residential suburb of the Los Angeles metropolitan area, at the base of the San Gabriel Mts.; inc. 1911. Plastics and transportation equipment are made in the city. The region was declared open government land in 1869 and a rush of homesteaders began. By the early 1900s it was covered with magnificent groves of orange and lemon trees. Although some citrus fruit is still grown in the area, the housing boom following World War II converted the city into a bedroom community.