91765 ZIP Code — Diamond Bar, CA

Los Angeles County, California

ZIP code 91765 is located in Diamond Bar, California, within Los Angeles County. It covers approximately 18.57 square miles and serves a population of 45,303 residents. This is a po box ZIP code in the Pacific (PT) timezone, served by area code 909.

About ZIP code 91765

The housing stock consists of predominantly single-family detached homes. Most homes were built in the 1980s, giving the area an established character. Median home value is $839,700. Owner-occupancy is high at 77%, well above the national average.

The gap between median ($105,712) and mean household income suggests income inequality — a small number of higher earners pull the average up. 34% of households receive Social Security income, suggesting a notable retiree or disability population.

The dominant occupation class is management, business, and professional, with education and healthcare as the leading industry. The average commute of 34 minutes is near the national average.

Educational attainment is high — 52% of residents hold a bachelor's degree or higher, well above the national average of 33%.

Notable community characteristics include Spanish spoken in 28% of households.

Overall, ZIP code 91765 reflects a community defined by a highly educated population, high homeownership, and a significant Social Security-dependent population.

45,303

population

18.57

sq mi land

PO Box

ZIP type

Pacific (PT)

timezone

91765 ZIP code map

Cities in ZIP code 91765

Below are the cities the US Postal Service accepts for ZIP code 91765. Using any city not on this list may result in mail delivery delays.

City	Status
Diamond Bar	Acceptable
Diamond Bar	Preferred

Nearby ZIP codes

91789 Walnut (2.4 mi) 91766 Pomona (4.5 mi) 92823 Brea (4.8 mi) 91748 Rowland Heights (5 mi) 91792 West Covina (5 mi) 91768 Pomona (5 mi) 92821 Brea (6 mi) 91709 Chino Hills (6.1 mi) 91791 West Covina (6.1 mi) 91724 Covina (6.2 mi) 91744 La Puente (7 mi) 92886 Yorba Linda (7.3 mi)

Demographics updated 05/2026

Population
Total population	45,303
Population density	2,440 / sq mi
State FIPS	06
County FIPS	037

Geography
Land area	18.57 sq mi
Water area	0.01 sq mi
Latitude	33.9945
Longitude	-117.8183
Timezone	Pacific (PT)
Area code	909

Total population by age

Gender

Race & ethnicity

Economics updated 05/2026

Household income

Income range	This ZIP	County avg	State avg
Under $50k	24.8%	36.2%	32.6%
$50k – $100k	24.4%	28.2%	27.7%
$100k – $200k	34.9%	24.5%	26.4%
Over $200k	15.9%	11.0%	13.3%

Demographics & statistics

45,303

Population

2,440

People per sq mi

44.9

Median age

$105,712

Median household income

$46,501

Per capita income

$839,700

Median home value

$2,310

Median monthly rent

77.1%

Home ownership

9.7%

Poverty rate

5.4%

Unemployment

12,308

Housing units

52.4%

Bachelor's or higher

Age distribution

Male Female

930

Under 5

1,008

993

5–9

1,075

1,471

10–14

1,593

1,385

15–19

1,501

968

20–24

1,049

2,620

25–34

2,839

2,526

35–44

2,737

3,302

45–54

3,578

1,978

55–59

2,143

1,432

60–64

1,551

2,625

65–74

2,845

1,019

75–84

1,105

494

85+

536

← Male

Female →

Age summary

Group	Count	%
Under 18	8,805	19.4%
18 and over	36,498	80.6%
65 and over	8,624	19.0%
Median age	44.9 years

Race & ethnicity

Asian 52.6%

White 19.5%

Hispanic or Latino 9.9%

Two or more races 7%

Other race 6.3%

Black or African American 3.6%

American Indian / Alaska Native 0.9%

Native Hawaiian / Pacific Islander 0.1%

Group	Count	%
Asian	26,454	52.6%
White	9,824	19.5%
Hispanic or Latino	4,991	9.9%
Two or more races	3,530	7%
Other race	3,171	6.3%
Black or African American	1,790	3.6%
American Indian / Alaska Native	470	0.9%
Native Hawaiian / Pacific Islander	64	0.1%

Household income

Income range	This ZIP	County avg	State avg
Under $50k	24.8%	36.2%	32.6%
$50k – $100k	24.4%	28.2%	27.7%
$100k – $200k	34.9%	24.5%	26.4%
Over $200k	15.9%	11.0%	13.3%

Under $10k 5.7%

$10k–$15k 1.6%

$15k–$25k 4.7%

$25k–$35k 5.7%

$35k–$50k 6.3%

$50k–$75k 13.4%

$75k–$100k 10.7%

$100k–$150k 19.3%

$150k–$200k 12.1%

$200k+ 20.4%

Range	% of households
Under $10k	5.7%
$10k–$15k	1.6%
$15k–$25k	4.7%
$25k–$35k	5.7%
$35k–$50k	6.3%
$50k–$75k	13.4%
$75k–$100k	10.7%
$100k–$150k	19.3%
$150k–$200k	12.1%
$200k+	20.4%
Median income	$105,712

Housing

Home values

Under $50k 0.7%

$50k–$100k 0.4%

$100k–$150k 0.5%

$150k–$200k 0.1%

$200k–$300k 0.4%

$300k–$500k 10.9%

$500k–$1M 61.3%

$1M+ 25.8%

Housing overview

Metric	Value
Median home value	$839,700
Median rent / month	$2,310
Owner occupied	77.1%
Renter occupied	22.9%
Vacant	4.3%
Single-family detached	70.2%
Large apartment buildings	5.7%
Mobile homes	0.1%
Median rooms	6.2
Avg household size (owned)	2.99

Year built

Era	%
2020 or later	0.0%
2010–2019	1.3%
2000–2009	2.6%
1990–1999	4.2%
1980–1989	38.3%
1970–1979	32.7%
1960–1969	17.8%
1950–1959	2.2%
1940–1949	0.4%
1939 or earlier	0.6%

Bedrooms

Size	% of units
No bedroom (studio)	2.7%
1 bedroom	3.6%
2 bedrooms	16.2%
3 bedrooms	27.7%
4 bedrooms	39.6%
5+ bedrooms	10.2%

Vehicles per household

Vehicles	% of households
No vehicle	2.4%
1 vehicle	22.8%
2 vehicles	41.9%
3 or more	32.9%

Heating fuel

Fuel type	%
Utility gas	79.8%
Electricity	17.3%
Propane / LP gas	1.5%
Solar	0.8%
No fuel used	0.7%

Households & families

Household type	Count	%
Married-couple family	9,454	62.7%
Cohabiting couple	440	2.9%
Male householder, no spouse	1,645	10.9%
Female householder, no spouse	3,542	23.5%
Households with children under 18	4,837	32.1%
Households with seniors (65+)	5,943	39.4%
Average household size	2.99

Marital status

Status	Male	Female
Never married	33.3%	26.7%
Married	58.9%	53.5%
Separated	0.3%	1.2%
Widowed	1.7%	9.0%
Divorced	5.7%	9.6%

Education

Less than 9th grade 4.1%

Some HS, no diploma 3.2%

HS graduate 14.0%

Some college, no degree 17.5%

Associate's degree 8.8%

Bachelor's degree 33.7%

Graduate / professional 18.8%

Metric	%
HS diploma or higher	92.7%
Bachelor's or higher	52.4%

School enrollment (ages 3–17)

Type	Count	%
Nursery / preschool	467	4.0%
Kindergarten	383	3.3%
Elementary school	4,190	35.9%
High school	2,221	19.0%
College / grad school	4,401	37.7%

Employment

Industry of employment

Education & healthcare 22.4%

Professional & management 13.5%

Retail trade 11.4%

Finance & real estate 9.3%

Arts, food & hospitality 8.7%

Manufacturing 8.0%

Wholesale trade 6.9%

Transportation & utilities 6.4%

Public administration 4.8%

Construction 3.7%

Other services 3.0%

Information 1.6%

Agriculture & mining 0.3%

Occupation

Category	%
Management, business & arts	53.4%
Service	12.5%
Sales & office	24.5%
Natural resources & construction	3.4%
Production & transportation	6.2%

Employment type

Type	%
Private sector	77.9%
Government	14.1%
Self-employed	7.9%
Unpaid family workers	0.1%

Commute

Method	%
Drive alone	74.0%
Carpool	9.1%
Public transit	1.8%
Walk	0.6%
Work from home	13.9%
Other means	0.6%
Avg commute (minutes)	34.4

Poverty

All people 9.7%

Under 18 years 10.8%

18 and over 9.4%

Married-couple families 6.0%

Female-led households 14.0%

Income support

Source	% of households
Social Security	33.7%
Retirement income	22.4%
Supplemental Security	4.0%
Cash public assistance	2.3%
Food stamps / SNAP	4.5%

Health indicators

Condition	%
Obesity	19.8%
High blood pressure	24.4%
High cholesterol	29.2%
Diabetes	8.7%
Heart disease	4.0%
Stroke	2.0%
Asthma	7.0%
Arthritis	14.7%
Kidney disease	2.1%
Pulmonary disease	3.4%
Cancer	4.7%

Behavior / access	%
Smoking	6.8%
Binge drinking	14.0%
No physical activity	16.0%
Less than 7 hrs sleep	31.1%
Depression	12.1%
Fair or poor health	9.4%
Poor mental health	11.1%
Poor physical health	6.6%
No health insurance	8.4%
Visited doctor (checkup)	65.2%
Visited dentist	69.5%
Cholesterol screening	93.1%
Teeth loss	5.6%

Veterans & disability

Veterans	Count	%
Civilian veterans	1,028	2.8%

Disability	%
Any disability	8.8%
Under 18	3.8%
18–64 years	5.5%
65 and over	24.7%

Health insurance coverage

Type	%
Private insurance	73.1%
Public insurance	32.4%
No insurance	3.8%
Uninsured under 19	3.9%

Language & origin

Language spoken at home (age 5+)

Language	Count	%
English only	43,365	95.7%
Spanish	12,141	28.0%
Other Indo-European	816	1.9%
Asian & Pacific Islander	454	1.0%
Other languages	10,745	24.8%

Place of birth & citizenship

Origin	Count	%
Native born (US)	25,016	55.2%
Born in same state	24,427	53.9%
Born in different state	20,712	45.7%
Foreign born	589	1.3%
Naturalized citizen	20,287	44.8%
Not a US citizen	14,412	71.0%

Ancestry

Ancestry	Count	%
French	1,020	2.3%
Italian	961	2.1%
Arab	504	1.1%
Polish	212	0.5%

Ancestry	Count	%
English	150	0.3%
German	91	0.2%
Norwegian	12	0%
Dutch	8	0%

Technology access

Metric	% of households
Computer access	33.3%
Internet access	98.2%

Source: U.S. Census Bureau, American Community Survey 2025 estimates.

Frequently asked questions about ZIP code 91765

What city is ZIP code 91765 in?

ZIP code 91765 is primarily assigned to Diamond Bar, California.

What county is ZIP code 91765 in?

ZIP code 91765 falls within Los Angeles County, California.

Is Spanish widely spoken in ZIP code 91765?

Approximately 28% of households in ZIP code 91765 speak Spanish as a primary language.

How educated is the population of ZIP code 91765?

52% of residents hold a bachelor's degree or higher — well above the national average of ~33%, reflecting a highly educated population.

What is the typical home value in ZIP code 91765?

The median home value in ZIP code 91765 is $839,700.

What is the median household income in ZIP code 91765?

The median household income in ZIP code 91765 is $105,712, above the national median of ~$75,000.

What timezone is ZIP code 91765 in?

ZIP code 91765 observes the PST timezone.