Residential delivery area · Connecticut
ZIP Code 06340: Groton, CT
ZIP code 06340 uses the postal name Groton, Connecticut and lies entirely in New London County (Census 2020 ZIP-county file). About 30,000 people live there (Census Bureau, ACS 2020-2024). Median household income is $81,792 (Census Bureau, ACS 2020-2024). By Census place, its land lies in Conning Towers-Nautilus Park (23%), Groton (14%), Long Hill (7%), Poquonock Bridge (6%), Noank (6%) and Groton Long Point (2%); 43% is outside any Census place.
- ACS2020-24
- Census2020
- FHFA2025
- ZBP2023
- IRS2022
- Town
- Groton · its only residential ZIP
- County
- New London County
- Census places
- Conning Towers-Nautilus Park (23%) census-designated place; Groton (14%); Long Hill (7%) census-designated place; Poquonock Bridge (6%) census-designated place
- House district
- CT-2 119th Congress
- State
- Connecticut
- Time zone
- Eastern
- Land area
- 22.5 sq mi · 1,325 people per sq mi
- PO Box ZIPs
- 06349 also use the name Groton
Where is ZIP code 06340?
06340 centers on 41.354°, -72.040° and covers 22.5 square miles of land plus 4.7 of water. It borders 5 ZIP codes: 06320, 06355, 06375, 06335, 06339.
The map draws ZIP code areas only. For the streets inside 06340, open its center on OpenStreetMap.
Source: U.S. Census Bureau, 2020 ZCTA cartographic boundaries and the 2023 Gazetteer (2020 ZCTAs); ZIP-to-county shares, Census places and House districts (119th Congress) from the Census 2020 relationship files (shares of land); metro area from the OMB delineation (July 2023); town name and time zone from simplemaps US ZIP Codes (CC BY 4.0).
How does 06340 compare with the rest of New London County?
| Measure | 06340 | In New London County | In CT |
|---|---|---|---|
| People (ACS 2020-2024) | 29,863 | 2nd of 33 | 31st of 288 |
| Median household income | $82k | 23rd of 26 | 183rd of 228 |
| Median home value | $295k | 20th of 26 | 183rd of 245 |
Its median household income is higher than in 64% of U.S. residential ZIP codes, and it is denser than 81% of all U.S. residential ZIP codes. ZIP codes at the ACS caps ($250,000 or more for household income, $2,000,000 or more for home value) share the top rank.
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B01003, B19013, B25077); ranks by PlainZIP over residential ZIP codes (ZCTAs).
How many people live in 06340?
The 2020 Census counted 29,788 people in 06340; the ACS, which samples households over 2020-2024, estimates 29,863. Between the 2010 and 2020 censuses its population fell 4.7% (its boundary stayed at least 90% the same).
- People, ACS 2020-2024
- 29,863
- 2020 Census count
- 29,788−4.7% since 2010 (31,242)
- Households
- 12,879
- Median age
- 33.7
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B01003, B01002, B11001); 2020 Census (DHC P1); 2010 Census (SF1 P1).
Who lives in 06340?
Of the 29,863 people the ACS estimates in 06340, 18.7% are under 18 and 16.7% are 65 or older. The largest group by race and Hispanic origin is White (not Hispanic) (65.6%), then Hispanic or Latino (14.2%).
- Under 1818.7%
- 18 to 6464.6%
- 65 and older16.7%
- White, not Hispanic65.6%
- Hispanic or Latino14.2%
- Asian, not Hispanic7.3%
- Other or two or more7.3%
- Black, not Hispanic5.6%
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B01001 age by sex, B03002 Hispanic or Latino origin by race); shares of the estimated population, small ZIP codes carry wide margins.
What do households in 06340 earn?
Median household income is $81,792 (ACS 2020-2024), the 23rd highest of the 26 ranked ZIP codes in New London County. It rose from $72,687 in 2015-2019 (in 2024 dollars), a change larger than the surveys' margins of error.
- Median household income
- $81,792
- Income per person
- $47,211
- Below the poverty line
- 12.7%
- Unemployed (of the labor force)
- 5.5%
- Adults 25+ with a bachelor's degree
- 39.2%
- Adjusted gross income per tax return, 2022
- $74,68214,120 returns; wages 71% of AGI (IRS)
Source: U.S. Census Bureau, ACS 2020-2024 and 2015-2019 5-year estimates (B19013, B19301, B17001, B23025, B15003; 2015-2019 dollars converted with the BLS CPI-U, 1.22699); IRS Statistics of Income, ZIP code data, tax year 2022 (adjusted gross income per return, filed under the address on the return).
What are homes worth in 06340?
FHFA's house price index for 06340, built from repeat sales and appraisals of the same homes, rose 100% from 2015 to 2025 and rose 73% from 2020 to 2025, and moved +11.2% in 2025.
- Median home value (owners' estimate)
- $294,700
- Median gross rent
- $1,599
- Homes owned by their occupants
- 44.5%
- Housing units
- 14,359
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B25077, B25064, B25003, B25001); FHFA House Price Index, annual five-digit ZIP, updated 2026-03-31.
What businesses are in 06340?
604 business establishments had a location in this ZIP code in 2023, 4 fewer than in 2018; the most are in accommodation and food services (ZIP Code Business Patterns).
- Accommodation and food services99
- Retail trade96
- Other services (except public administration)86
- Health care and social assistance83
- Professional, scientific, and technical services71
- Finance and insurance33
Source: U.S. Census Bureau, ZIP Code Business Patterns 2023 and 2018 (establishments with paid employees, by the business's ZIP code).
Which ZIP codes are next to 06340?
| ZIP | Town | People | Household income | Distance |
|---|---|---|---|---|
| 06320 | New London | 27,703 | $59k | 3.2 mi |
| 06355 | Mystic | 12,173 | $137k | 3.6 mi |
| 06375 | Quaker Hill | 3,670 | $112k | 5.6 mi |
| 06335 | Gales Ferry | 6,307 | $118k | 5.6 mi |
| 06339 | Ledyard | 9,113 | $106k | 6.6 mi |
| 06385 | Waterford | 15,966 | $101k | 6.1 mi (near) |
| 06378 | Stonington | 5,555 | $136k | 7.1 mi (near) |
| 06390 | Fishers Island, NY | 72 | $98k | 7.1 mi (near) |
Source: PlainZIP from the Census 2020 ZCTA boundaries (shared edges) and internal points; figures ACS 2020-2024.
Which other ZIP codes use the name Groton?
1 more ZIP code carries the postal name Groton, CT without a residential delivery area: PO boxes at the post office, or a single organization with its own ZIP code. The Census Bureau publishes no figures for it.
| ZIP | County |
|---|---|
| 06349 | New London County |
Source: GeoNames postal codes (CC BY 4.0), downloaded 2026-10-09; a ZIP code with no Census ZCTA has no residential delivery area.