Get API Key →
US ZIP Code Profile

ZIP Code 02138
Cambridge, Massachusetts

ZIP code 02138 is in Cambridge, located in Middlesex County, Massachusetts, within the Boston-Cambridge-Newton metro area. Its 2020 Census population was 37,982. The estimated median adjusted gross income per tax return is $81,826, and about 22% of filers report $200,000 or more.

2020 Population
37,982
Census ZCTA
County
Middlesex
FIPS 25017
Median income (est.)
$81,826
IRS SOI 2022
Land Area
2.741 mi²
+ 0.313 mi² water

01Location & Geography

Authoritative geographic identifiers from the U.S. Census Bureau, ANSI, and FIPS standards.

Primary CityCambridge, MA
CountyMiddlesex County (FIPS 25017)
StateMassachusetts (FIPS 25)
Metro Area (MSA)Boston-Cambridge-Newton, MA-NH Metro Area (14460)
Census Region / DivisionNortheast Region · New England Division
Coordinates42.37964, -71.135155
Land / Water Area2.741 mi² land · 0.313 mi² water

02Income & Economics

Distribution of the 14,470 individual tax returns filed in 02138 by adjusted gross income bracket (IRS SOI, 2022).

< $25K
16.9%
$25K–$50K
15.6%
$50K–$75K
14.6%
$75K–$100K
10.5%
$100K–$200K
20.2%
$200K+
22.2%
The $200,000+ bracket accounts for 81% of 02138's total adjusted gross income, from 22% of returns — a concentration that drives the gap between the median ($81,826) and the average.
Estimated median = median adjusted gross income per tax return, interpolated from IRS SOI brackets. Differs from U.S. Census household income.

03Income Over Time

Year-over-year change in 02138's IRS income metrics, 2020–2022.

Median income (2021→2022)
$81,826
▲ 0.2%
Filers earning $200K+
22.2%
▼ 1.0 pt
Total filers
14,470
▲ 3.1%
GET /zipc/v2/zipcodes/02138/soi?year=… $75K 2020 $82K 2021 $82K 2022
Median = adjusted gross income per return, interpolated from IRS SOI brackets. Figures are nominal (not inflation-adjusted).

04Population Trend

Decennial U.S. Census population for the 02138 ZCTA.

2000
35,407
 
2010
36,314
▲ +2.6%
2020
37,982
▲ +4.6%

05Nearby ZIP Codes — Live Radius Search

Drag the slider to filter ZIP codes by distance from 02138. Powered by the same radius endpoint developers call from the API.

GET /zipc/v2/radius

ZIP codes within range of 02138

Cambridge and its immediate neighbors, sorted by distance.

3.0 mi
GET /zipc/v2/distance

Distance from 02138 to any ZIP

Enter a 5-digit ZIP to calculate the distance.

06USPS Postal Details

Delivery and facility attributes from the monthly USPS dataset.

ZIP ClassificationNon-Unique Zip
Facility TypePost Office
Carrier Route SortB
USPS Finance Number241065
City AliasesCambridge

07Frequently Asked Questions

What county is ZIP code 02138 in?

ZIP code 02138 is in Middlesex County, Massachusetts (county FIPS code 25017).

What city is ZIP code 02138?

The primary USPS city for 02138 is Cambridge, MA.

What metro area (MSA) is 02138 in?

02138 is part of the Boston-Cambridge-Newton, MA-NH Metro Area (MSA code 14460).

What is the population of ZIP code 02138?

The 2020 Census population of 02138 was 37,982 residents.

What is the median income in ZIP code 02138?

Based on IRS Statistics of Income data, the estimated median adjusted gross income per tax return in 02138 is about $81,826, with around 22% of filers reporting $200,000 or more. Note that adjusted gross income is a tax measure and differs from U.S. Census household income.