Residential delivery area · New Hampshire
ZIP Code 03857: Newmarket, NH
ZIP code 03857 uses the postal name Newmarket, New Hampshire and lies entirely in Rockingham County (Census 2020 ZIP-county file). About 9,500 people live there (Census Bureau, ACS 2020-2024). Median household income is $100,845 (Census Bureau, ACS 2020-2024). By Census place, 18% of its land lies in Newmarket (a census-designated place); 82% is outside any Census place.
- ACS2020-24
- Census2020
- FHFA2025
- ZBP2023
- IRS2022
- Town
- Newmarket · its only residential ZIP
- County
- Rockingham County
- Census places
- Newmarket census-designated place
- Metro area
- Boston-Cambridge-Newton, MA-NH
- House district
- NH-1 119th Congress
- State
- New Hampshire
- Time zone
- Eastern
- Land area
- 12.6 sq mi · 751 people per sq mi
Where is ZIP code 03857?
03857 centers on 43.071°, -70.947° and covers 12.6 square miles of land plus 1.6 of water. It borders 7 ZIP codes: 03856, 03824, 03885, 03861, 03840, 03801, 03042.
The map draws ZIP code areas only. For the streets inside 03857, 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 03857 compare with the rest of Rockingham County?
| Measure | 03857 | In Rockingham County | In NH |
|---|---|---|---|
| People (ACS 2020-2024) | 9,463 | 10th of 37 | 38th of 247 |
| Median household income | $101k | 29th of 32 | 82nd of 158 |
| Median home value | $455k | 23rd of 34 | 51st of 191 |
Its median household income is higher than in 82% of U.S. residential ZIP codes, and it is denser than 76% 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 03857?
The 2020 Census counted 9,430 people in 03857; the ACS, which samples households over 2020-2024, estimates 9,463. Between the 2010 and 2020 censuses its population grew 4.7% (its boundary stayed at least 90% the same).
- People, ACS 2020-2024
- 9,463
- 2020 Census count
- 9,430+4.7% since 2010 (9,006)
- Households
- 4,345
- Median age
- 41.2
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 03857?
Of the 9,463 people the ACS estimates in 03857, 15.6% are under 18 and 16.1% are 65 or older. The largest group by race and Hispanic origin is White (not Hispanic) (91.1%).
- Under 1815.6%
- 18 to 6468.3%
- 65 and older16.1%
- White, not Hispanic91.1%
- Other or two or more5.6%
- Hispanic or Latino1.4%
- Asian, not Hispanic1.3%
- Black, not Hispanic0.6%
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 03857 earn?
Median household income is $100,845 (ACS 2020-2024), the 29th highest of the 32 ranked ZIP codes in Rockingham County. It is not measurably different from 2015-2019 ($90,471 in 2024 dollars): the change is within the surveys' margins of error.
- Median household income
- $100,845±$13,234
- Income per person
- $58,507
- Below the poverty line
- 4.6%
- Unemployed (of the labor force)
- 1.0%
- Adults 25+ with a bachelor's degree
- 49.7%
- Adjusted gross income per tax return, 2022
- $95,2195,230 returns; wages 72% 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 03857?
FHFA's house price index for 03857, built from repeat sales and appraisals of the same homes, rose 124% from 2015 to 2025 and rose 72% from 2020 to 2025, and moved +12.4% in 2025.
- Median home value (owners' estimate)
- $455,000
- Median gross rent
- $1,671
- Homes owned by their occupants
- 52.9%
- Housing units
- 4,500
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 03857?
152 business establishments had a location in this ZIP code in 2023, 1 fewer than in 2018; the most are in professional, scientific, and technical services (ZIP Code Business Patterns).
- Professional, scientific, and technical services19
- Other services (except public administration)18
- Accommodation and food services17
- Construction16
- Health care and social assistance16
- Retail trade14
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 03857?
| ZIP | Town | People | Household income | Distance |
|---|---|---|---|---|
| 03856 | Newfields | 2,023 | $198k | 2.5 mi |
| 03824 | Durham | 15,080 | $124k | 3.5 mi |
| 03885 | Stratham | 7,754 | $152k | 4.5 mi |
| 03861 | Lee | 4,576 | $132k | 4.5 mi |
| 03840 | Greenland | 4,106 | $163k | 5.6 mi |
| 03801 | Portsmouth | 23,484 | $107k | 7.1 mi |
| 03042 | Epping | 7,430 | $104k | 7.3 mi |
| 03833 | Exeter | 22,817 | $119k | 6.6 mi (near) |
| 03823 | Madbury | 2,203 | $148k | 7.2 mi (near) |
Source: PlainZIP from the Census 2020 ZCTA boundaries (shared edges) and internal points; figures ACS 2020-2024.