New Jersey State Senate District 21

State Legislative District Profile (Upper Chamber)

Overview

District ID
nj-sd-021
State
New Jersey
Chamber
Upper chamber (state senate)
District Code
021
Land Area
137.8 sq mi
Water Area
1.21 sq mi

Boundary

Boundary of New Jersey State Senate District 21

Boundary as GeoJSON

Source: U.S. Census Bureau TIGER/Line state legislative district boundaries.

Counties

CountyOverlapShare of district landShare of county land
Somerset County77.61 sq mi56.3%25.7%
Union County32.43 sq mi23.5%31.6%
Morris County23.22 sq mi16.9%5.0%
Middlesex County4.55 sq mi3.3%1.5%

Showing all 4 counties

Places

PlaceOverlapShare of district landShare of place land
Bernardsville borough12.84 sq mi9.3%100.0%
Basking Ridge CDP6.75 sq mi4.9%100.0%
Westfield town6.72 sq mi4.9%100.0%
Watchung borough6.02 sq mi4.4%100.0%
Summit city5.99 sq mi4.3%100.0%
Peapack and Gladstone borough5.73 sq mi4.2%100.0%
Far Hills borough4.85 sq mi3.5%100.0%
Gillette CDP4.32 sq mi3.1%100.0%
Mountainside borough4.00 sq mi2.9%100.0%
Lyons CDP3.85 sq mi2.8%100.0%
New Providence borough3.69 sq mi2.7%100.0%
Middlesex borough3.49 sq mi2.5%100.0%
Millington CDP2.60 sq mi1.9%100.0%
Chatham borough2.35 sq mi1.7%100.0%
Stirling CDP2.34 sq mi1.7%100.0%
Green Village CDP1.93 sq mi1.4%82.3%
Liberty Corner CDP1.92 sq mi1.4%100.0%
The Hills CDP1.73 sq mi1.3%61.1%
Dunellen borough1.06 sq mi0.8%100.0%
Garwood borough0.65 sq mi0.5%100.0%
Springfield CDP0.39 sq mi0.3%100.0%

Showing all 21 places

Overlapping Congressional Districts

Congressional districtPopulation in bothShare of this district's populationShare of the congressional district's populationShare of this district's land
NJ District 7182,37179.5%23.6%87.9%
NJ District 1222,2739.7%2.9%3.3%
NJ District 1120,1958.8%2.6%8.3%
NJ District 104,4541.9%0.6%0.5%

Source: U.S. Census Bureau 2020 blocks and 2025 block equivalency files (119th Congress, 2024 state legislative plans).

Voters

Registered Voters
186,346
Active Voters
172,879 (92.8%)

Party Registration

PartyVotersShare
Democratic62,43233.5%
Republican53,97129.0%
Unaffiliated68,59636.8%
Other parties1,3470.7%
No party recorded00.0%

Turnout by Cycle

CycleGeneralDemocratic PrimaryRepublican Primary
2025–2026107,422 (57.6%)22,198 (11.9%)16,907 (9.1%)
2023–2024134,782 (72.3%)16,284 (8.7%)15,440 (8.3%)
2021–2022104,048 (55.8%)14,763 (7.9%)16,175 (8.7%)
2019–2020132,353 (71.0%)25,127 (13.5%)16,696 (9.0%)
2017–201898,195 (52.7%)15,630 (8.4%)11,706 (6.3%)
2015–2016101,316 (54.4%)16,697 (9.0%)13,790 (7.4%)
2013–201461,890 (33.2%)7,291 (3.9%)9,048 (4.9%)
2011–201280,552 (43.2%)3,397 (1.8%)6,912 (3.7%)

Turnout counts today's registered voters with a counted ballot in the cycle's elections (the odd and even year), as a share of today's registered voters. Voters who have since left the rolls are not counted.

Browse the voter list for this district (premium access; sign-in required)

Source: Civitech voter file snapshot as of 01/02/2026. These are registered voters, separate from the Census population figures. Counts under 10 are suppressed and shown as "<10".

Demographics

Total Population
231,039 (± 320)
Median Age
43.6
Median Household Income
$177,704 (± $4,778)
High School Graduate or Higher (age 25+)
95.7%
Bachelor's Degree or Higher (age 25+)
67.6%

Population by Age

GroupPeopleShare
Under 1855,45924.0%
18 to 64133,88457.9%
65 and over41,69618.0%

Population by Race and Hispanic Origin

GroupPeopleShare
Hispanic or Latino (any race)27,90612.1%
White, not Hispanic156,46067.7%
Black, not Hispanic7,0053.0%
Asian, not Hispanic29,72312.9%
American Indian / Alaska Native, not Hispanic640.0%
Native Hawaiian / Pacific Islander, not Hispanic170.0%
Some other race, not Hispanic1,5750.7%
Two or more races, not Hispanic8,2893.6%

Source: U.S. Census Bureau, American Community Survey 2020-2024 ACS 5-year estimates (tables B01001, B01002, B01003, B03002, B15003, B19013) for this state legislative district. Estimates are survey-based; ± figures are 90% margins of error.

Citizen Voting Age Population

Total Citizen Population
213,027
Citizen Voting Age Population (CVAP)
159,718

Citizen Population by Race/Ethnicity

GroupCitizensShare
Non-Hispanic190,85989.6%
Hispanic22,16010.4%
White155,35872.9%
Black6,4523.0%
Asian22,55010.6%
American Indian / Alaska Native530.0%
Native Hawaiian / Pacific Islander560.0%
Two or More Races4860.2%

Citizen Voting Age Population by Race/Ethnicity

GroupCVAPShare
Non-Hispanic145,69691.2%
Hispanic14,0248.8%
White121,57776.1%
Black6,1213.8%
Asian17,00810.6%
American Indian / Alaska Native5690.4%
Native Hawaiian / Pacific Islander400.0%
Two or More Races3920.2%

Source: Redistricting Data Hub / U.S. Census Bureau CVAP Special Tabulation (2020-2024 ACS 5-year).