Diamond Bar is an affluent community in eastern Los Angeles County, California, United States. The population was 55,544 at the 2010 census, down from 56,287 at the 2000 census. It is named after the “diamond over a bar” branding iron registered in 1918 by ranch owner Frederick E. Lewis. Located at the junction of the Pomona and Orange freeways, Diamond Bar is primarily residential with shopping centers interspersed throughout the city. It is surrounded by the suburban cities, such as Brea, Walnut, Chino Hills, and Rowland Heights. The city features a public Los Angeles County golf course. Diamond Bar has the first hydrogen fueling station to be built in Southern California, near the South Coast Air Quality Management District (AQMD) building. In 1840, Jose de la Luz Linares received the 4,340-acre (1,760ha) Mexican land grant Rancho Los Nogales (Ranch of the Walnut Trees) from Governor Juan Alvarado. The land grant included Brea Canyon and the eastern Walnut Valley. Linares died in 1847, and his widow sold a part of the ranch to Ricardo Vejar for $100 in merchandise, 100 calves, and the assumption of her late husband’s debts. Vejar also owned the Rancho San Jose to the east and acquired the rest of Rancho Nogales over the next 10 years.