Diamond Bar is a city in Los Angeles County, California, home to about 53,355 people across 15 square miles. Its ZIP code is 91765, and parts of 91789 are in Diamond Bar too.
Homes sold for a median of $560 per square foot in the three months ending August 2026, a balanced market.
Mostly Diamond Bar
Mostly Walnut; part is in Diamond Bar
Each card is that ZIP code’s whole market, including any part outside Diamond Bar. Seller’s market: under 4 months of supply; buyer’s market: over 6. Methodology
We’re writing up Diamond Bar’s story and what everyday life there is like, for people thinking about moving in.
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| Nearest major airport | Ontario International Airport (ONT)13 miles away |
|---|---|
| Nearest city of 250,000+ | Anaheim, CA11 miles away |
| Nearest city of 1 million+ | Los Angeles, CA34 miles away |
Straight-line distances from the center of Diamond Bar; driving is longer.
Source: Airports from OurAirports (scheduled passenger service); city centers and populations from the U.S. Census Bureau.
Source: Members of Congress from the congress-legislators project; districts from the Census Bureau’s relationship files; governor and mayor from Wikidata.
Diamond Bar had 55,072 residents in the 2020 census, down 2% since 2000.
It’s the 174th largest of 1,563 towns in California by population.
Los Angeles County grew from 170,298 residents in 1900 to 10,014,009 in 2020.
Los Angeles County, 1900–2020
Source: U.S. Census Bureau decennial censuses (counties 1900–1990 from the Bureau’s historical county file).
Average highs peak around 92°F in summer, and winter lows average 42°F. About 14.5 inches of rain and melted snow fall in a typical year.
Source: NOAA 1991–2020 climate normals, Pomona/Fairplex, CA weather station (6 miles away).
3,987,736 jobs at 304,988 businesses in Los Angeles County. The biggest industries by employees:
Source: U.S. Census Bureau County Business Patterns 2023 (private employers; jobs counted where people work).
354 doctors and other health care providers list an office in Diamond Bar.
Nearest hospitals
Providers with an office here
| Primary care doctors | 44 |
|---|---|
| Specialist doctors | 19 |
| Dentists | 73 |
| Nurse practitioners and physician assistants | 40 |
| Mental health providers | 86 |
| Physical and occupational therapists | 66 |
| Optometrists | 10 |
| Chiropractors | 16 |
| Pharmacies | 9 |
Source: Hospitals from CMS Hospital General Information (ratings are CMS overall star ratings); straight-line distances; providers from the CMS National Plan and Provider Enumeration System (NPPES), by practice address and primary specialty.
Parks (18 nearby)
Grocery stores (7 nearby)
Pharmacies (1 nearby)
Libraries (2 nearby)
Museums
Theaters and performance venues
Counts are within about 2.5 miles of the center of town.
Source: Map data © OpenStreetMap contributors (openstreetmap.org/copyright), as mapped by volunteers; it can miss places or include closed ones.
Established in 1989.
Notable people born here
Source: Wikidata (wikidata.org), the free knowledge base; people are listed by place of birth.
Public schools here are run by Pomona Unified, Walnut Valley Unified. Check each district’s attendance zones for a specific address.
| School | Grades | Students | Type | Distance |
|---|---|---|---|---|
| Armstrong ElementaryDiamond Bar | K–6 | 251 | Public | 0.9 mi |
| Castle Rock ElementaryDiamond Bar | K–5 | 684 | Public | 2.9 mi |
| Evergreen ElementaryDiamond Bar | K–5 | 709 | Public | 2.3 mi |
| Golden Springs ElementaryDiamond Bar | K–6 | 388 | Public | 1.4 mi |
| Maple Hill ElementaryDiamond Bar | K–5 | 556 | Public | 1.0 mi |
| Pantera ElementaryDiamond Bar | K–6 | 512 | Public | 1.4 mi |
| Quail Summit ElementaryDiamond Bar | K–5 | 696 | Public | 0.9 mi |
| Chaparral MiddleDiamond Bar | 6–8 | 1,349 | Public | 0.9 mi |
| Lorbeer MiddleDiamond Bar | 7–8 | 688 | Public | 0.7 mi |
| Diamond Bar HighDiamond Bar | 9–12 | 2,563 | Public | 2.2 mi |
| School | Grades | Students | Affiliation | Distance |
|---|---|---|---|---|
| Landmark Christian PreschoolDiamond Bar | Pre-K–K | 12 | Christian (no specific denomination) | 3.6 mi |
| Mt Calvary Lutheran SchoolDiamond Bar | Pre-K–8 | 192 | Lutheran Church–Missouri Synod | 0.6 mi |
| Diamond Bar Montessori AcademyDiamond Bar | K | 7 | Nonsectarian | 1.1 mi |
Source: U.S. Department of Education, NCES: Common Core of Data (2024-2025) for public schools; Private School Universe Survey (2023-2024) for private schools. Listed by address; we don’t rate schools.
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Shares ZIP codes with Walnut, Rowland Heights, Pomona and Industry.
Town boundaries don’t always match ZIP codes: a ZIP code can cross into neighboring towns, and a town can share a ZIP code with its neighbors. Facts describe the town itself; market figures describe whole ZIP codes.