† Citizen voting-age population estimated for prior cycles; 2004 predates the ACS and is extrapolated. Source: ACS 5-year, table B05003.
——
D+60R+60
20042024
Boundary by 2024 margin · Precinct returns · VEST · MIT Election Lab
People and households
Who lives here
Exact values for this place, its state, and the United States.
Race · ethnicity · ancestry
Communities and origins
GroupDiamond BarCaliforniaUnited States
Chinese18.5%3.9%1.3%
Filipino14.7%3.3%0.9%
Korean8.4%1.2%0.4%
Asian Indian4.2%2.3%1.4%
Vietnamese4.2%1.7%0.6%
Japanese3.8%0.6%0.2%
Taiwanese1.7%0.3%—
Cambodian1.3%——
Mexican12.7%32.3%11.3%
Salvadoran1.7%2.0%0.7%
Guatemalan1.1%1.3%0.5%
Honduran0.2%—0.3%
Puerto Rican0.2%0.6%1.8%
German2.5%6.8%12.5%
Irish2.2%5.9%9.4%
English2.2%6.3%9.5%
American1.8%2.8%5.3%
Italian1.5%3.4%4.8%
Armenian1.2%——
Polish0.7%0.9%2.2%
French0.6%1.3%1.6%
African American†2.7%4.4%9.9%
African0.2%0.3%0.5%
Aztec4.0%0.3%—
Maya2.4%——
Samoan0.8%——
Hispanic or Latino counts residents of any race; the race groups count only their non-Hispanic residents, so the groups are mutually exclusive and sum to 100%. Expand a row to see ancestries reported within that group.
Age and life stage
Measure
Diamond Bar
California
United States
Median age
45.7
37.9
39.1
Age 18–24
6.4%
9.1%
9.2%
Age 65 and older
21.0%
15.6%
17.2%
Household economy
Measure
Diamond Bar
California
United States
Median household income
$108,281
$99,122
$84,427
Poverty rate
10.0%
12.0%
12.5%
Bachelor's degree or higher (25+)
52.8%
36.6%
35.6%
Languages at home
Measure
Diamond Bar
California
United States
Speaks a non-English language at home
63.3%
44.4%
22.3%
Spanish
9.6%
28.4%
13.6%
Other Indo-European
4.4%
3.4%
2.0%
Korean
6.8%
1.0%
0.3%
Chinese (incl. Mandarin & Cantonese)
33.3%
3.5%
1.1%
Religious landscape
Measure
Diamond Bar
California
United States
Catholic
—
26.2%
18.6%
Evangelical Protestant
—
9.0%
16.5%
Unclaimed / not counted
—
55.2%
51.5%
American Community Survey 2024 5-year (CVAP, income, age, poverty, education, language, race, ancestry) · presidential returns from MIT Election Lab through 2024 · 2020 U.S. Religion Census (ASARB) — congregational adherents; unclaimed is the residual not counted by congregations.
Diamond Bar, California
presidential history
Presidential margin, 2004–2024
Democratic minus Republican, by election
Presidential margin over time
Year
Margin (D minus R)
2004
−1.8%
2008
+12.3%
2012
+11.3%
2016
+21.5%
2020
+19.8%
2024
+7.3%
DemocraticRepublican
6 presidential elections
Third column names the leading third-party or independent finisher. Source · MIT Election Lab · ICPSR · VEST (precinct-level 2024). Swing · margin change from the prior cycle. vs U.S. · margin relative to the national result that year. Third-party votes in 2012 are allocated from certified county totals by this place's share of each county's two-party vote — that cycle's precinct source records two-party splits. † 2004, 2012, 2024 sub-county results are estimated: the source's block-level detail for these cycles was unreliable — either county/municipality-level consolidated reporting (COVID-era) or a precinct-to-block allocation that misplaced votes — so the figures are allocated from the constituent county totals in proportion to the place and scaled to certified totals.
Year
Won
Democratic
Republican
Other
Margin
Swing
vs U.S.
Total
D
51.8%Harris11,800
44.4%Trump10,130
3.8%
D+7.3
R+12.5
D+8.8
22,801
D
59.1%Biden15,894
39.3%Trump10,575
1.6%
D+19.8
R+1.8
D+15.3
26,893
D
58.1%Clinton11,738
36.6%Trump7,388
5.3%
D+21.5
D+10.2
D+19.5
20,191
D
54.4%Obama11,133
43.1%Romney8,813
2.5%
D+11.3
R+1.0
D+7.5
20,453
D
56.1%Obama12,260
43.8%McCain9,571
0.2%
D+12.3
D+14.1
D+5.0
21,866
R
48.8%Kerry10,785
50.6%Bush11,192
0.6%
R+1.8
—
D+0.6
22,117
Diamond Bar's electorate is roughly 60% Asian American, with high rates of college education and homeownership that have made it a closely watched bellwether in Los Angeles County's rapidly shifting San Gabriel Valley corridor.
Across the recorded series it reached a Democratic high of 21.5 points in 2016 and a Republican high of 1.8 points in 2004. Between 2020 and 2024 the city moved 12.5 points toward the Republican candidate; the 2024 margin was 7.3 points.
A population of 53,355, a 13% non-Hispanic-white share, and a median household income of $108,281 describe the city. The city's voting pattern over the last decade is most similar to that of Temple City and Walnut.
Akashic
Political twins — cities
The cities whose fingerprint — 2000–2024 trajectory, demographics, ancestry, religion — sits closest to this one, and why.
Twin score (0–100) = weighted cosine between tier-standardized fingerprints: presidential margins 2000–2024 with 12-yr trend and elasticity, ACS income, age, education, population and race, top reported ancestries, and religious adherence — chips name the closest-shared dimensions and the widest gap. Re-weight the groups in the twins explorer.
In 2024, Diamond Bar, California voted Democratic by 7.3 points (D+7.3), carried by the Democratic candidate. Out of 22,801 votes cast, 11,800 went Democratic and 10,130 went Republican.
When did Diamond Bar, California last vote Republican?
The most recent presidential election in which Diamond Bar, California voted Republican was 2004.
How many people live in Diamond Bar, California?
Diamond Bar, California has a population of 53,355 according to the 2024 American Community Survey 5-year estimates from the US Census Bureau.
What is the median household income in Diamond Bar, California?
Median household income in Diamond Bar, California is $108,281 — above the national median of $80,734. The California state median is $99,122.
What is the political history of Diamond Bar, California?
Akashic tracks 6 presidential elections in Diamond Bar, California from 2004 to 2024. Of those, 5 went Democratic and 1 went Republican.
