Diamond Bar is a city in eastern Los Angeles County, California. It is named after the “diamond over a bar” branding iron registered in 1918 by ranch owner Frederick E. Lewis.
Positioned in the south-eastern corner of the San Gabriel Valley in eastern Los Angeles County, Diamond Bar is approximately 27 miles (43 km) east of Downtown Los Angeles. Neighboring communities include Walnut, Rowland Heights, and Pomona. Diamond Bar is also adjacent to the Inland Empire region, with Chino Hills directly to the east, and to the south of Diamond Bar lie the cities of Brea and La Habra in Orange County.
As of the 2010 census the City had a population of 55,544, and in 2019 the population was estimated to be 55,720. According to the 2010 United States Census, Diamond Bar has a median household income at one of the top earning percentiles in the country at $88,422, with 5.9% of the population living below the federal poverty line.
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 communities of Brea, Walnut, Chino Hills, Rowland Heights, Pomona, and City of Industry. The City also features a public Los Angeles County golf course. It is also home to the Diamond Bar Country Estates, a private guarded community.
Northern Diamond Bar is a part of the Pomona Unified School District. Southern Diamond Bar is a part of the Walnut Valley Unified School District. The City is also served by International Polytechnic High School. It also has the first hydrogen fueling station to be built in Southern California, near the South Coast Air Quality Management District (SCAQMD) building.
Both the CA-60 Freeway and the CA-57 Freeway run through Diamond Bar. The I-10 Freeway is just north of the city and CA-71 is just east of the city. Major thoroughfares include Grand Avenue, Diamond Bar Boulevard, Pathfinder Road, Golden Springs Drive, and Brea Canyon Road.