Diamond Bar is a city in Los Angeles County, California. The city was incorporated on April 18, 1989. Like much of the surrounding area, Diamond Bar’s history is steeped in an 1840 land grant which exchanged hands and fates many times. By the late 1800s Diamond Bar Ranch, as it was then known, was one of the largest working cattle ranches in the western U.S. In the 1950’s the land was acquired by Transamerica Corporation for the purpose of developing one the nation’s first master-planned communities. The first homes were built in 1960. Multiple developer’s took over in the 1970s and 1980s.
Today, Diamond Bar is an affluent community, nestled in the junction between the Pomona and Orange freeways. It is primarily residential with shopping centers interspersed throughout the city. In additional to numerous parks, and a spectacular community center, Diamond Bar features a Los Angeles County Golf Course.
According to the City’s 2010 Comprehensive Annual Financial Report the top employers in the city are: South Coast Air Quality Management District, Allstate, Travelers.
Diamond Bar has several elementary, junior high, and high schools. The city is divided into two school districts. Those south of Grand Ave are part of the Walnut Valley Unified School District and in the northern portion are part of the Pomona Unified School District.