state senate districtHawaii 21st State Senate District
presidential margin
2004–2024 · Democratic minus Republican
2004R+9.9
2008D+30.1
2012D+26.9
2016D+11.9
2020D+6.2
2024R+4.2
net swing · 2004→2024D+5.7R+9.9 → R+4.2
vs. U.S. · 2024R+2.7R+4.2 vs R+1.5
presidential returns
2024 turnout 45.4% of 43,264 citizens 18+
Year
Democrat
Republican
Others
Total
CVAP
Turnout
2024
9,233
10,054
338
19,625
43,264
45.4%
2020
11,061
9,748
385
21,194
41,806†
50.7%
2016
7,417
5,731
1,058
14,206
41,605†
34.1%
2012
8,361
4,782
176
13,319
39,927†
33.4%
2008
8,612
4,584
167
13,363
37,899†
35.3%
2004
6,128
7,476
40
13,644
35,870†
38.0%
† Citizen voting-age population estimated for prior cycles from the constituent-county ACS trend anchored to the current figure. 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
GroupHI SD 21HawaiiUnited States
Filipino12.8%14.3%0.9%
Japanese11.7%11.7%0.2%
Chinese4.7%4.1%1.3%
Korean1.6%1.4%0.4%
Vietnamese0.9%0.8%0.6%
Asian Indian0.2%0.2%1.4%
Thai0.2%0.2%—
Laotian0.2%——
Mexican4.4%3.4%11.3%
Puerto Rican4.3%3.3%1.8%
Spanish1.6%1.3%—
Spaniard1.0%0.7%—
Cuban0.3%—0.7%
German4.2%5.8%12.5%
English3.4%5.1%9.5%
Irish3.3%4.7%9.4%
Portuguese1.8%3.2%—
Italian1.4%2.1%4.8%
American1.0%1.0%5.3%
French0.8%1.2%1.6%
Polish0.6%0.7%2.2%
Native Hawaiian7.7%6.1%—
Samoan1.8%0.9%—
Marshallese0.8%0.6%—
Chuukese0.6%0.3%—
Tongan0.5%0.3%—
Chamorro0.5%0.2%—
African American†1.8%1.1%9.9%
African0.2%—0.5%
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
HI SD 21
Hawaii
United States
Median age
34.7
41
39.1
Age 18–24
8.7%
8.0%
9.2%
Age 65 and older
19.5%
20.5%
17.2%
Household economy
Measure
HI SD 21
Hawaii
United States
Median household income
$117,119
$100,389
$84,427
Poverty rate
9.1%
10.0%
12.5%
Bachelor's degree or higher (25+)
38.5%
36.2%
35.6%
Languages at home
Measure
HI SD 21
Hawaii
United States
Speaks a non-English language at home
26.0%
24.7%
22.3%
Spanish
2.0%
2.1%
13.6%
Chinese (incl. Mandarin & Cantonese)
3.4%
2.5%
1.1%
Tagalog (incl. Filipino)
4.9%
4.4%
0.6%
Other Asian & Pacific Island
11.5%
11.6%
1.1%
Religious landscape
Measure
HI SD 21
Hawaii
United States
Catholic
—
18.6%
18.6%
Evangelical Protestant
—
8.9%
16.5%
Unclaimed / not counted
—
59.7%
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.
Hawaii 21st State Senate District
presidential history
Presidential margin, 2004–2024
Democratic minus Republican, by election
Presidential margin over time
Year
Margin (D minus R)
2004
−9.9%
2008
+30.1%
2012
+26.9%
2016
+11.9%
2020
+6.2%
2024
−4.2%
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 sub-county results are estimated: the source's block-level detail for this cycle 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
R
47.0%Harris9,233
51.2%Trump10,054
1.7%
R+4.2
R+10.4
R+2.7
19,625
D
52.2%Biden11,061
46.0%Trump9,748
1.8%
D+6.2
R+5.7
D+1.7
21,194
D
52.2%Clinton7,417
40.3%Trump5,731
7.4%
D+11.9
R+15.0
D+9.8
14,206
D
62.8%Obama8,361
35.9%Romney4,782
1.3%
D+26.9
R+3.3
D+23.0
13,319
D
64.4%Obama8,612
34.3%McCain4,584
1.2%
D+30.1
D+40.0
D+22.9
13,363
R
44.9%Kerry6,128
54.8%Bush7,476
0.3%
R+9.9
—
R+7.4
13,644
current representation
Current officeholders
DMike GabbardState Senate · 21
State legislative officeholder from OpenStates nightly current-legislator data.
Anchored in urban Honolulu, this district delivers presidential margins exceeding 40 points, reflecting a dense, heavily Democratic electorate that has shown little competitive variation in recent cycles.
Across the recorded series it reached a Democratic high of 30.1 points in 2008 and a Republican high of 9.9 points in 2004. Between 2020 and 2024 the district moved 10.4 points toward the Republican candidate; the 2024 margin was 4.2 points.
A population of 59,486, a 12% non-Hispanic-white share, and a median household income of $117,119 describe the district. The district's voting pattern over the last decade is most similar to that of State Senate District 20 and State Senate District 17.
Akashic
Political twins — state-senate districts
The state-senate districts 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.
Compare two places, side by side
Twelve curated comparisons line up election history, demographics, and the divergence story for two places at a glance. Browse all comparisons →
Cite this page
All citations released under CC BY 4.0. Attribution: Akashic Intelligence.
Hawaii 21st State Senate District. Akashic. https://akashic.app/sld-upper/15021/. Accessed May 20, 2026. License: CC BY 4.0.
How did Hawaii 21st State Senate District vote in 2024?
In 2024, Hawaii 21st State Senate District voted Republican by 4.2 points (R+4.2), carried by the Republican candidate. Out of 19,625 votes cast, 9,233 went Democratic and 10,054 went Republican.
When did Hawaii 21st State Senate District last vote Democratic?
The most recent presidential election in which Hawaii 21st State Senate District voted Democratic was 2020.
How many people live in Hawaii 21st State Senate District?
Hawaii 21st State Senate District has a population of 59,486 according to the 2024 American Community Survey 5-year estimates from the US Census Bureau.
What is the median household income in Hawaii 21st State Senate District?
Median household income in Hawaii 21st State Senate District is $117,119 — above the national median of $80,734. The Hawaii state median is $100,389.
What is the political history of Hawaii 21st State Senate District?
Akashic tracks 6 presidential elections in Hawaii 21st State Senate District from 2004 to 2024. Of those, 4 went Democratic and 2 went Republican.
