Dorchester, MA

ZIP code 02121 is assigned to Dorchester, MA, and falls within Suffolk County. Like every US postal code, it began as a mail-routing device rather than a geographic boundary — the US Postal Service groups delivery routes under a single code so carriers and sorting equipment can process mail efficiently. Today it also serves as a practical shorthand for the area itself: roughly 28,298 people live inside it.

At 15,004 residents per square mile spread over 1.886 square miles, 02121 reads as a dense urban area. It is a populous postal code, and density shapes almost everything else on this page — how people get to work, whether they own or rent, and what housing costs.

Household earnings are well below the national median. At $38,565, 02121 ranks among the lower-income postal codes, ahead of 5% of them. The US median for comparison is $70,109. Bear in mind that median income describes the midpoint household, not the average — it is not pulled upward by a handful of very high earners the way a mean would be.

Housing in 02121 costs well above the national median. A typical home is valued at $548,100 against a US median of $207,500, and median gross rent runs $1,316 a month. This is firmly renter territory — 76.9% of occupied homes are rented, a pattern typical of city centres, student areas and neighbourhoods with a lot of apartment stock.

The building stock is dominated by small multi-family buildings of two to four units, which account for 52.2% of housing units here. The median construction year is 1950, making the housing here mid-century.

The population skews younger than the country as a whole, with a median age of 34.2 against 42 nationally. The average household holds 2.73 people, and 63.5% are family households.

Getting to work takes 37.4 minutes on average one way. The dominant mode is drove alone at 39.9% of workers, while 34.6% take public transit. Commute patterns are one of the better proxies for how a place actually functions day to day.

Beyond addressing mail, 02121 does a lot of quiet administrative work. Retailers use it to calculate shipping and sales tax at checkout. Insurers use it to set premiums, since risk profiles vary geographically. Employers and marketers use it to define service areas. Government agencies use it to route benefits and organise reporting. If you have ever been asked for a postal code by a form that clearly does not intend to send you anything, this is why.

For anyone weighing a move, 02121 offers a compact profile of Dorchester: 28,298 residents, a median household income of $38,565, 20.5% of adults holding a bachelor's degree or higher, and an unemployment rate of 9.6%. A handful of figures like these answer more relocation questions than most neighbourhood guides do.

One caution worth repeating: a postal code is not a neighbourhood. 02121 may cover parts of several distinct areas, and a single neighbourhood in Dorchester may be split across more than one code. Boundaries also shift as USPS adjusts delivery routes. Treat the figures here as describing a delivery area, which is what they actually measure.