Residential delivery area · Massachusetts
ZIP Code 02421: Lexington, MA
ZIP code 02421 is in Lexington, Massachusetts, entirely in Middlesex County (Census 2020 ZIP-county file). About 18,000 people live there (Census Bureau, ACS 2020-2024), the more populous of Lexington's 2 residential ZIP codes. Median household income is $227,813 (Census Bureau, ACS 2020-2024).
- ACS2020-24
- Census2020
- FHFA2025
- ZBP2023
- IRS2022
- Town
- Lexington · 2 residential ZIPs
- County
- Middlesex County
- Census places
- Lexington census-designated place
- Metro area
- Boston-Cambridge-Newton, MA-NH
- House district
- MA-5 119th Congress
- State
- Massachusetts
- Time zone
- Eastern
- Land area
- 9.6 sq mi · 1,889 people per sq mi
Where is ZIP code 02421?
02421 centers on 42.439°, -71.240° and covers 9.6 square miles of land plus 0.2 of water. It borders 8 ZIP codes: 02420, 02451, 01731, 02452, 01773, 02476, 02478, 01730.
The map draws ZIP code areas only. For the streets inside 02421, 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 02421 compare with the rest of Lexington?
| Measure | 02421 | In Lexington | In Middlesex County | In MA |
|---|---|---|---|---|
| People (ACS 2020-2024) | 18,080 | 1st of 2 | 42nd of 83 | 144th of 539 |
| Median household income | $228k | 2nd of 2 | 8th of 78 | 11th of 406 |
| Median home value | $1.21M | 1st of 2 | 12th of 80 | 22nd of 449 |
Its median household income is higher than in 99% of U.S. residential ZIP codes, and it is denser than 84% 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 02421?
The 2020 Census counted 18,950 people in 02421; the ACS, which samples households over 2020-2024, estimates 18,080. Between the 2010 and 2020 censuses its population grew 9.3% (its boundary stayed at least 90% the same).
- People, ACS 2020-2024
- 18,080
- 2020 Census count
- 18,950+9.3% since 2010 (17,342)
- Households
- 6,824
- Median age
- 48.2
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 02421?
Of the 18,080 people the ACS estimates in 02421, 25.4% are under 18 and 22.8% are 65 or older. The largest group by race and Hispanic origin is White (not Hispanic) (54.6%), then Asian (not Hispanic) (35.7%).
- Under 1825.4%
- 18 to 6451.9%
- 65 and older22.8%
- White, not Hispanic54.6%
- Asian, not Hispanic35.7%
- Other or two or more5.4%
- Hispanic or Latino3.0%
- Black, not Hispanic1.4%
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 02421 earn?
Median household income is $227,813 (ACS 2020-2024), the 8th highest of the 78 ranked ZIP codes in Middlesex County. It is not measurably different from 2015-2019 ($218,843 in 2024 dollars): the change is within the surveys' margins of error.
- Median household income
- $227,813±$31,387
- Income per person
- $112,662
- Below the poverty line
- 6.4%
- Unemployed (of the labor force)
- 2.4%
- Adults 25+ with a bachelor's degree
- 83.2%
- Adjusted gross income per tax return, 2022
- $338,9798,580 returns; wages 62% 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 02421?
FHFA's house price index for 02421, built from repeat sales and appraisals of the same homes, rose 43% from 2015 to 2025 and rose 25% from 2020 to 2025, and moved −6.5% in 2025.
- Median home value (owners' estimate)
- $1,205,700
- Median gross rent
- $2,948
- Homes owned by their occupants
- 75.9%
- Housing units
- 6,903
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 02421?
582 business establishments had a location in this ZIP code in 2023, 16 more than in 2018; the most are in professional, scientific, and technical services (ZIP Code Business Patterns).
- Professional, scientific, and technical services175
- Health care and social assistance91
- Other services (except public administration)50
- Accommodation and food services39
- Retail trade32
- Finance and insurance28
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 02421?
| ZIP | Town | People | Household income | Distance |
|---|---|---|---|---|
| 02420 | Lexington | 16,215 | $245k | 1.8 mi |
| 02451 | Waltham | 17,393 | $122k | 2.6 mi |
| 01731 | Hanscom Afb | 2,110 | $105k | 2.9 mi |
| 02452 | Waltham | 15,808 | $118k | 3.1 mi |
| 01773 | Lincoln | 4,891 | $209k | 3.7 mi |
| 02476 | Arlington | 17,708 | $151k | 3.7 mi |
| 02478 | Belmont | 27,175 | $183k | 4.3 mi |
| 01730 | Bedford | 14,707 | $172k | 4.7 mi |
| 02474 | Arlington | 28,642 | $151k | 4.4 mi (near) |
Source: PlainZIP from the Census 2020 ZCTA boundaries (shared edges) and internal points; figures ACS 2020-2024.