Diamond Bar ZIP Code List — Los Angeles County, CA
There is one unique ZIP code in Diamond Bar, California and it is 91765. Area code: 909.
1
ZIP codes
18.57
sq mi land
0.01
sq mi water
909
area code
Diamond Bar, CA ZIP code map
About Diamond Bar, CA
Diamond Bar, California, is a picturesque city located in the eastern region of Los Angeles County. Known for its suburban charm and scenic hills, it offers a blend of residential neighborhoods and commercial areas. The city is also recognized for its family-friendly atmosphere, making it a desirable place to live and raise children.
Location & geography
Situated approximately 30 miles east of downtown Los Angeles, Diamond Bar is surrounded by several neighboring cities, including Walnut to the north, Chino Hills to the east, Industry to the south, and Pomona to the west. The city covers a land area of 37.14 square miles, with a slight water area of 0.01 square miles. The terrain is predominantly hilly, providing residents with beautiful views and numerous outdoor recreational opportunities.
Community & economy
Diamond Bar is characterized by its diverse community, which includes families, professionals, and retirees. The local economy is bolstered by a mix of retail businesses, healthcare services, and light manufacturing industries. Residents enjoy a high quality of life, supported by well-maintained parks, community events, and educational resources.
Transportation
Diamond Bar is conveniently located near several major highways, including the Interstate 57 and the Interstate 60, which provide easy access to the greater Los Angeles area. The city is also served by the Ontario International Airport, located roughly 20 miles away, offering both domestic and international flights. Public transit options, such as buses, are available for commuting within the region.
History
Diamond Bar was incorporated as a city in 1989, although its history dates back to the 1840s when it was originally a cattle ranch. The city's name is derived from the diamond-shaped bar brand used by the cattle ranch owners. Over the years, Diamond Bar has evolved into a thriving suburban community, reflecting California's overall growth and development.
Did you know?
One little-known fact about Diamond Bar is that it was originally established as part of a large cattle ranch and has preserved many of its natural landscapes. Additionally, the city is home to a variety of parks and recreational facilities that promote outdoor activities and community engagement.
Source: U.S. Census Bureau, American Community Survey 2025 estimates.
Frequently asked questions
What is the ZIP code for Diamond Bar, CA?
Diamond Bar, CA has one ZIP code: 91765.
What is the main ZIP code for Diamond Bar, CA?
The primary ZIP code for Diamond Bar, CA is 91765. The city uses area code 909 for phone service.
What county is Diamond Bar, CA in?
Diamond Bar is located in Los Angeles County, California.
How many ZIP codes are in Diamond Bar, CA?
Diamond Bar, CA has 1 ZIP code.
What is the ZIP code for Diamond Bar's central commercial district along Diamond Bar Boulevard?
The main commercial areas along Diamond Bar Boulevard, including the Diamond Bar Town Center and surrounding retail districts, are located in ZIP code 91765.
What ZIP code covers the residential neighborhoods near Diamond Bar High School?
Diamond Bar High School and the surrounding residential neighborhoods in the central part of the city are all within ZIP code 91765.
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