Residential delivery area · New Hampshire
ZIP Code 03878: Somersworth, NH
ZIP code 03878 is in Somersworth, New Hampshire, entirely in Strafford County (Census 2020 ZIP-county file). About 12,000 people live there (Census Bureau, ACS 2020-2024). Median household income is $75,136 (Census Bureau, ACS 2020-2024).
- ACS2020-24
- Census2020
- FHFA2025
- ZBP2023
- IRS2022
- Town
- Somersworth · its only residential ZIP
- County
- Strafford County
- Census places
- Somersworth
- Metro area
- Boston-Cambridge-Newton, MA-NH
- House district
- NH-1 119th Congress
- State
- New Hampshire
- Time zone
- Eastern
- Land area
- 9.8 sq mi · 1,244 people per sq mi
Where is ZIP code 03878?
03878 centers on 43.253°, -70.888° and covers 9.8 square miles of land plus 0.2 of water. It borders 5 ZIP codes: 03869, 03901, 03820, 03868, 03867.
The map draws ZIP code areas only. For the streets inside 03878, 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 03878 compare with the rest of Strafford County?
| Measure | 03878 | In Strafford County | In NH |
|---|---|---|---|
| People (ACS 2020-2024) | 12,205 | 4th of 16 | 30th of 247 |
| Median household income | $75k | 11th of 12 | 131st of 158 |
| Median home value | $318k | 10th of 15 | 141st of 191 |
Its median household income is higher than in 55% of U.S. residential ZIP codes, and it is denser than 80% 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 03878?
The 2020 Census counted 11,919 people in 03878; the ACS, which samples households over 2020-2024, estimates 12,205. Between the 2010 and 2020 censuses its population grew 0.8% (its boundary stayed at least 90% the same).
- People, ACS 2020-2024
- 12,205
- 2020 Census count
- 11,919+0.8% since 2010 (11,824)
- Households
- 5,245
- Median age
- 38.5
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 03878?
Of the 12,205 people the ACS estimates in 03878, 19.8% are under 18 and 14.1% are 65 or older. The largest group by race and Hispanic origin is White (not Hispanic) (83.3%).
- Under 1819.8%
- 18 to 6466.2%
- 65 and older14.1%
- White, not Hispanic83.3%
- Other or two or more6.1%
- Hispanic or Latino5.9%
- Asian, not Hispanic2.5%
- Black, not Hispanic2.2%
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 03878 earn?
Median household income is $75,136 (ACS 2020-2024), the 11th highest of the 12 ranked ZIP codes in Strafford County. It is not measurably different from 2015-2019 ($81,886 in 2024 dollars): the change is within the surveys' margins of error.
- Median household income
- $75,136±$12,640
- Income per person
- $42,408
- Below the poverty line
- 11.2%
- Unemployed (of the labor force)
- 2.8%
- Adults 25+ with a bachelor's degree
- 31.3%
- Adjusted gross income per tax return, 2022
- $68,7696,670 returns; wages 79% 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 03878?
FHFA's house price index for 03878, built from repeat sales and appraisals of the same homes, rose 126% from 2015 to 2025 and rose 71% from 2020 to 2025, and moved +3.7% in 2025.
- Median home value (owners' estimate)
- $317,900
- Median gross rent
- $1,479
- Homes owned by their occupants
- 58.0%
- Housing units
- 5,690
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 03878?
318 business establishments had a location in this ZIP code in 2023, 30 more than in 2018; the most are in retail trade (ZIP Code Business Patterns).
- Retail trade76
- Health care and social assistance36
- Other services (except public administration)34
- Manufacturing30
- Accommodation and food services29
- Professional, scientific, and technical services26
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 03878?
| ZIP | Town | People | Household income | Distance |
|---|---|---|---|---|
| 03869 | Rollinsford | 2,456 | $87k | 3.2 mi |
| 03901 | Berwick, ME | 8,175 | $95k | 3.9 mi |
| 03820 | Dover | 33,440 | $95k | 4.6 mi |
| 03868 | Rochester | 6,133 | $82k | 5.6 mi |
| 03867 | Rochester | 22,732 | $79k | 6.2 mi |
| 03839 | Rochester | 4,279 | $88k | 5.0 mi (near) |
| 03823 | Madbury | 2,203 | $148k | 6.1 mi (near) |
| 03908 | South Berwick, ME | 7,431 | $98k | 7.0 mi (near) |
Source: PlainZIP from the Census 2020 ZCTA boundaries (shared edges) and internal points; figures ACS 2020-2024.