Southeastern Connecticut Planning Region, Connecticut population
County or county equivalent · Official geographic code 09180
· Annual resident population estimate
U.S. Census Bureau · Population Estimates Program · Vintage 2025
+844 residents (+0.30%) since July 1, 2024.
Southeastern Connecticut Planning Region had an estimated 284,015 residents on July 1, 2025, the 6th most populous of 9 counties and county equivalents in Connecticut. Its population grew 0.30% between July 2024 and July 2025, compared with +0.38% for Connecticut and +0.52% for the United States.
- Population change, 2020–2025
- +5,632July 1 to July 1 · +2.02%
- Land-area density, 2025
- 474.8People per square mile · 2025 land area
- Rank in Connecticut, 2025
- 6 of 9256 of 3,144 nationally
Southeastern Connecticut Planning Region population history
Open historical explorerThe six July 1 estimates in the table belong to one consistent Vintage 2025 series. The Census Bureau revises earlier years when it releases a new vintage; a figure from an older publication may differ from the value below.
Annual estimates · 2020–2025 · Vertical scale shown on chart.
The highest observed population in this annual series was 284,015 in 2025. This is a peak within 2020–2025 coverage, not an all-time record.
| Reference date | Population | Annual change |
|---|---|---|
| July 1, 2020 | 278,383 | — |
| July 1, 2021 | 279,596 | +1,213 |
| July 1, 2022 | 279,495 | -101 |
| July 1, 2023 | 280,776 | +1,281 |
| July 1, 2024 | 283,171 | +2,395 |
| July 1, 2025 | 284,015 | +844 |
Why is the April 2020 estimates base different from a census count?
The PEP estimates base here is 280,467 residents on April 1, 2020. It incorporates the Census Bureau’s corrections and geographic revisions and serves as the starting point for this annual series. It is not labeled an original 2020 census count. The chart starts at July 1, 2020, so its five-year change uses two July observations. Read about measurement types.
Growth and density
Between July 1, 2020 and July 1, 2025, Southeastern Connecticut Planning Region gained 5,632 residents, a 2.02% increase. The annualized change over these five elapsed years was +0.40%. Annualized change is a summary of the interval; it does not imply that the population changed at that rate in every year.
The 2025 Gazetteer reports 598.14 square miles of land. Dividing the July 1, 2025 population by that compatible land area gives 474.8 people per square mile. Water area is excluded. Density depends on geographic boundaries. It describes this entire geography, rather than a typical neighborhood or built-up area.
Calculations use unrounded source values. Population counts are displayed as integers, percentages to two decimals and density to one decimal. Calculation methods · Growth calculator
Components of population change
The published components cover July 1, 2024 through June 30, 2025. Natural change equals births minus deaths. Net migration is arrivals minus departures; it does not establish why people moved.
| Component | People |
|---|---|
| Births | 2,577 |
| Deaths | 2,753 |
| Natural change | -176 |
| Net domestic migration | +358 |
| Net international migration | +642 |
| Residual | +20 |
| Total population change | +844 |
Reconciliation: natural change + net domestic migration + net international migration + residual = +844. Births and deaths are already included in natural change and must not be added again. Source: co-est2025-alldata.csv; Vintage 2025.
How Southeastern Connecticut Planning Region compares
Growth rates below use the same Vintage 2025 series for every row, so they can be compared directly. A county’s rate reflects all of its towns and unincorporated areas together.
| Geography | Population · 2025 | Growth · 2024–25 | Growth · 2020–25 |
|---|---|---|---|
| Southeastern Connecticut Planning Region | 284,015 | +0.30% | +2.02% |
| Connecticut | 3,688,496 | +0.38% | +3.04% |
| United States | 341,784,857 | +0.52% | +3.08% |
Southeastern Connecticut Planning Region demographics: age, race and income
The median age in Southeastern Connecticut Planning Region is 41.1 years, compared with 41.1 in Connecticut. 35.8% of adults 25 and older hold a bachelor’s degree or higher, and the median household income is $86,586. About 10.7% of residents live below the poverty level, and 8.8% were born outside the United States.
These are American Community Survey 5-year estimates for 2020–2024. They describe the 60 months ending in December 2024, come from a sample survey with the margins of error shown, and are separate from the July 1, 2025 population estimate above.
| Characteristic | Southeastern Connecticut Planning Region | Margin | Connecticut | U.S. |
|---|---|---|---|---|
| Age and sex | ||||
| Median age | 41.1 | ±0.3 | 41.1 | 38.9 |
| Under 18 years | 19.3% | ±0.4 | 20.2% | 22.0% |
| 65 years and over | 19.5% | ±0.5 | 18.5% | 17.2% |
| Female | 50.0% | ±<0.1 | 50.9% | 50.5% |
| Race and Hispanic origin | ||||
| Hispanic or Latino (any race) | 15.0% | ±<0.1 | 18.3% | 19.3% |
| White alone, not Hispanic | 70.6% | ±0.3 | 61.9% | 57.4% |
| Black alone, not Hispanic | 4.9% | ±0.3 | 9.8% | 11.9% |
| Asian alone, not Hispanic | 3.7% | ±0.1 | 4.7% | 5.9% |
| American Indian and Alaska Native, not Hispanic | 0.3% | ±0.1 | 0.1% | 0.5% |
| Native Hawaiian and Pacific Islander, not Hispanic | 0.0% | ±<0.1 | 0.0% | 0.2% |
| Some other race, not Hispanic | 0.6% | ±0.2 | 0.9% | 0.6% |
| Two or more races, not Hispanic | 4.8% | ±0.4 | 4.3% | 4.3% |
| Born outside the United States | 8.8% | ±0.4 | 15.7% | 14.1% |
| Households and education | ||||
| Households | 115,768 | ±890 | 1,434,007 | 129,227,496 |
| Average household size | 2.32 | ±0.02 | 2.46 | 2.53 |
| Bachelor’s degree or higher, age 25+ | 35.8% | ±1.1 | 42.5% | 35.7% |
| Income and poverty | ||||
| Median household income | $86,586 | ±$1,937 | $95,781 | $80,734 |
| Below the poverty level | 10.7% | ±0.8 | 10.0% | 12.5% |
Margins are 90% margins of error. Percentages are computed from published Summary File counts with Census Bureau margin formulas. ACS survey population: 279,971; 2024 boundaries. Source and download
Geographic context
County equivalents include parishes, boroughs, census areas, independent cities, DC and Connecticut planning regions where represented by Census. The places listed below are whole-city observations and can extend into other counties. Summing them will not reproduce this county total.
| Place | Population · 2025 | Change · 2024–25 | Growth · 2024–25 | People / sq. mi. |
|---|---|---|---|---|
| NorwichConnecticut · Incorporated place · 0956200 | 40,001 | -32 | -0.08% | 1,425.4 |
| New LondonConnecticut · Incorporated place · 0952280 | 28,003 | -18 | -0.06% | 4,994.5 |
| GrotonConnecticut · Incorporated place · 0934180 | 10,160 | -3 | -0.03% | 3,295.1 |
| Jewett CityConnecticut · Incorporated place · 0939940 | 3,456 | -4 | -0.12% | 4,904.3 |
| StoningtonConnecticut · Incorporated place · 0973700 | 1,017 | +1 | +0.10% | 2,982.2 |
| Groton Long PointConnecticut · Incorporated place · 0934460 | 522 | +2 | +0.38% | 1,221.8 |
Showing 6 of 6 related records.
Connecticut population · State city directory · City proper versus county versus metro
Connecticut planning regions replaced the former counties as Census statistical county equivalents. The annual estimates within this vintage use the current units. Do not attach a former-county series solely by name or code.
Connecticut counties and county equivalents with nearby population ranks
Neighboring 2025 population ranks within Connecticut. Similar population does not imply similar density, boundaries or demographics.
| Place | Population · 2025 | Change · 2024–25 | Growth · 2024–25 | People / sq. mi. |
|---|---|---|---|---|
| Naugatuck Valley Planning Region | 463,349 | +1,869 | +0.41% | 1,122.5 |
| Greater Bridgeport Planning Region | 337,697 | +1,306 | +0.39% | 2,408.8 |
| Lower Connecticut River Valley Planning Region | 177,311 | +264 | +0.15% | 418.1 |
| Northwest Hills Planning Region | 114,690 | +410 | +0.36% | 145.8 |
Source, citation and downloads
U.S. Census Bureau, Population Estimates Program, Vintage 2025, co-est2025-alldata.csv, variable POPESTIMATE2025; Southeastern Connecticut Planning Region, Connecticut, geographic code 09180; resident population 284,015 on July 1, 2025; boundaries January 1, 2025. https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/counties/totals/co-est2025-alldata.csv. Retrieved September 30, 2026. US Population Data snapshot pep-2025-r1, transformation 1.
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