Residential delivery area · Massachusetts
ZIP Code 02451: Waltham, MA
ZIP code 02451 is in Waltham, Massachusetts, entirely in Middlesex County (Census 2020 ZIP-county file). About 17,000 people live there (Census Bureau, ACS 2020-2024), the 2nd most populous of Waltham's 3 residential ZIP codes. Median household income is $122,335 (Census Bureau, ACS 2020-2024).
- ACS2020-24
- Census2020
- FHFA2025
- ZBP2023
- IRS2022
- Town
- Waltham · 3 residential ZIPs
- County
- Middlesex County
- Census places
- Waltham
- Metro area
- Boston-Cambridge-Newton, MA-NH
- House district
- MA-5 119th Congress
- State
- Massachusetts
- Time zone
- Eastern
- Land area
- 5.3 sq mi · 3,269 people per sq mi
- PO Box ZIPs
- 02454 also use the name Waltham
Where is ZIP code 02451?
02451 centers on 42.402°, -71.253° and covers 5.3 square miles of land plus 0.7 of water. It borders 5 ZIP codes: 02452, 02453, 02421, 01773, 02493.
The map draws ZIP code areas only. For the streets inside 02451, 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 02451 compare with the rest of Waltham?
| Measure | 02451 | In Waltham | In Middlesex County | In MA |
|---|---|---|---|---|
| People (ACS 2020-2024) | 17,393 | 2nd of 3 | 45th of 83 | 158th of 539 |
| Median household income | $122k | 1st of 3 | 60th of 78 | 163rd of 406 |
| Median home value | $753k | 2nd of 3 | 41st of 80 | 98th of 449 |
Its median household income is higher than in 91% of U.S. residential ZIP codes, and it is denser than 90% 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 02451?
The 2020 Census counted 17,953 people in 02451; the ACS, which samples households over 2020-2024, estimates 17,393. Between the 2010 and 2020 censuses its population grew 3.0% (its boundary stayed at least 90% the same).
- People, ACS 2020-2024
- 17,393
- 2020 Census count
- 17,953+3.0% since 2010 (17,426)
- Households
- 7,481
- Median age
- 40.3
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 02451?
Of the 17,393 people the ACS estimates in 02451, 14.5% are under 18 and 18.8% are 65 or older. The largest group by race and Hispanic origin is White (not Hispanic) (55.4%), then Asian (not Hispanic) (17.0%).
- Under 1814.5%
- 18 to 6466.8%
- 65 and older18.8%
- White, not Hispanic55.4%
- Asian, not Hispanic17.0%
- Hispanic or Latino15.2%
- Black, not Hispanic8.5%
- Other or two or more3.9%
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 02451 earn?
Median household income is $122,335 (ACS 2020-2024), the 60th highest of the 78 ranked ZIP codes in Middlesex County. It fell from $136,916 in 2015-2019 (in 2024 dollars), a change larger than the surveys' margins of error.
- Median household income
- $122,335
- Income per person
- $67,455
- Below the poverty line
- 8.3%
- Unemployed (of the labor force)
- 3.5%
- Adults 25+ with a bachelor's degree
- 56.0%
- Adjusted gross income per tax return, 2022
- $111,3979,660 returns; wages 76% 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 02451?
FHFA's house price index for 02451, built from repeat sales and appraisals of the same homes, rose 80% from 2015 to 2025 and rose 36% from 2020 to 2025, and moved +4.3% in 2025.
- Median home value (owners' estimate)
- $753,000
- Median gross rent
- $2,677
- Homes owned by their occupants
- 59.3%
- Housing units
- 7,748
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 02451?
1,195 business establishments had a location in this ZIP code in 2023, 69 fewer than in 2018; the most are in professional, scientific, and technical services (ZIP Code Business Patterns).
- Professional, scientific, and technical services226
- Accommodation and food services169
- Health care and social assistance133
- Administrative and support and waste management and remediation services97
- Finance and insurance85
- Construction75
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 02451?
| ZIP | Town | People | Household income | Distance |
|---|---|---|---|---|
| 02452 | Waltham | 15,808 | $118k | 1.7 mi |
| 02453 | Waltham | 31,591 | $115k | 2.3 mi |
| 02421 | Lexington | 18,080 | $228k | 2.6 mi |
| 01773 | Lincoln | 4,891 | $209k | 3.4 mi |
| 02493 | Weston | 11,579 | $250k+ | 3.8 mi |
| 02478 | Belmont | 27,175 | $183k | 3.7 mi (near) |
| 02465 | West Newton | 11,697 | $194k | 3.8 mi (near) |
| 02466 | Auburndale | 8,679 | $170k | 3.9 mi (near) |
Source: PlainZIP from the Census 2020 ZCTA boundaries (shared edges) and internal points; figures ACS 2020-2024.