Greensboro, MD

ZIP code 21639 is assigned to Greensboro, MD, and falls within Caroline 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 4,621 people live inside it.

At 140 residents per square mile spread over 33.087 square miles, 21639 reads as a rural area. It is a smaller postal code by population, 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 run below the national median. At $59,274, 21639 sits in the lower half, ahead of 31% 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 21639 costs close to the national median. A typical home is valued at $270,300 against a US median of $207,500, and median gross rent runs $1,017 a month. Ownership dominates: 71.4% of occupied homes are owner-occupied, which usually signals an established residential area with relatively low turnover.

The building stock is dominated by detached single-family houses, which account for 80.6% of housing units here. The median construction year is 1982, making the housing here from the later twentieth century.

The population skews broadly in line with the national age profile, with a median age of 37.3 against 42 nationally. The average household holds 2.75 people, and 63.8% are family households.

Getting to work takes 35.9 minutes on average one way. The dominant mode is drove alone at 77.4% of workers.

Beyond addressing mail, 21639 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, 21639 offers a compact profile of Greensboro: 4,621 residents, a median household income of $59,274, 12.2% of adults holding a bachelor's degree or higher, and an unemployment rate of 3.0%. 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. 21639 may cover parts of several distinct areas, and a single neighbourhood in Greensboro 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.