21837 ZIP Code, Mardela Springs, MD
21837 is a ZIP code in Mardela Springs, Maryland in Wicomico County. It covers 44 square miles of land. The closest ZIP codes are 21830, 21861 and 21659. 2,891 people live here in 1,123 households. It is rural, with fewer than 100 people per square mile, and most homes are owner-occupied (87%). Median household income is $62,880, well below the Maryland median of $103,678.
Quick facts
- Mailing city: Mardela Springs, MD
- County: Wicomico County
- Land area: 44 sq mi
- Population: 2,891
- Median household income: $62,880
- Carrier routes: 2 (976 homes)
Key figures
| Measure | Value |
|---|---|
| Residents | 2,891 |
| Households | 1,123 |
| Median household income | $62,880 |
| Income per person | $34,456 |
| Median age | 40.8 |
| Homeowners | 87.2% |
| Median home value | $227,400 |
| Median rent | $1,115 |
| Bachelor's degree or higher | 18.0% |
| Average commute (minutes) | 25.6 |
| Households with kids under 18 | 22.3% |
| Moved in the past year | 9.0% |
| Below the poverty line | 5.7% |
| Broadband internet | 77.1% |
| Speak a non-English language at home | 1.8% |
Household income
| % of households | Value |
|---|---|
| <$10K | 1.5% |
| $10–15K | 3.8% |
| $15–25K | 7.5% |
| $25–35K | 2.9% |
| $35–50K | 11.8% |
| $50–75K | 27.4% |
| $75–100K | 15.5% |
| $100–150K | 16.2% |
| $150–200K | 7.5% |
| $200K+ | 5.9% |
Age
| % of all residents | Value |
|---|---|
| <10 | 10.9% |
| 10–19 | 16.8% |
| 20–24 | 5.1% |
| 25–34 | 11.2% |
| 35–44 | 10.3% |
| 45–54 | 15.5% |
| 55–64 | 11.5% |
| 65–74 | 6.8% |
| 75+ | 12.0% |
Tenure
| % of housing units | Value |
|---|---|
| Owned, with mortgage | 51.2% |
| Owned outright | 32.1% |
| Rented | 12.0% |
| Vacant | 4.7% |
Type of building
| % of housing units | Value |
|---|---|
| Detached house | 84.6% |
| Townhome | 1.9% |
| 2–4 units | 0.0% |
| 5–19 units | 0.6% |
| 20+ units | 0.0% |
| Mobile / other | 12.9% |
Businesses in 21837
33 business establishments with 190 employees (ZIP Codes Business Patterns 2023).
- Retail Trade: 7
- Transportation and Warehousing: 4
- Other Services (except Public Administration): 4
- Construction: 3
- Professional, Scientific, and Technical Services: 3
- Administrative and Support and Waste Management and Remediation Services: 3
EDDM carrier routes
21837 has 2 USPS carrier routes with 976 residential and 26 business mailboxes. Open the EDDM route map.
Carrier routes in 21837
21837 has 2 USPS carrier routes (2 rural (R)) with 976 residential and 26 business mailboxes. Routes range from 403 homes (R002) to 573 homes (R001); the median route has 488 homes. The Census counted 1,123 households in 21837 (2020–2024 average); USPS counts current mailboxes, including new and vacant homes.
| Homes per route | Routes |
|---|---|
| 1–249 | 0 |
| 250–499 | 1 |
| 500–749 | 1 |
| 750–999 | 0 |
| 1,000–1,499 | 0 |
| 1,500+ | 0 |
Best routes in 21837 for…
Most businesses
For B2B offers: office supplies, cleaning, IT, catering and commercial services.
- Route R001 — USPS business mailboxes 16, 573 homes
- Route R002 — USPS business mailboxes 10, 403 homes
Select these 2 routes on the route map
Every carrier route in 21837
| Route | Type | Homes | Businesses | Est. median income | Est. owners | Est. families with kids | Est. moved in past year |
|---|---|---|---|---|---|---|---|
| R001 | Rural | 573 | 16 | $84,931 | — | — | — |
| R002 | Rural | 403 | 10 | $89,901 | — | — | — |
Income, owners, families and movers are estimates for each route (how we estimate them); mailbox counts are current USPS figures. Open 21837 on the EDDM route map.
How route demographics are estimated
Mailbox counts come from USPS; demographics are estimates
The number of homes and businesses on each carrier route is the current USPS EDDM count. The Census Bureau does not publish figures for carrier routes, so income, homeownership, ages, families, movers and housing age on a route are EDDM2GO estimates built from Census block groups (neighborhood areas of roughly 600 to 3,000 people).
How a route gets its figures: the block-group length-share method
We trace each route's streets every 25 meters and record which block group each stretch falls in. The route's homes are spread along its streets in proportion to length, so a route with 60% of its street length in one block group is assumed to have 60% of its homes there. Each block group then contributes its Census counts in proportion to the share of its housing units that sit on the route (capped at the whole block group). Medians are recalculated from the combined income, home-value and age brackets, the way the Census Bureau computes them, not averaged.
Margins of error
Census survey figures carry a margin of error at 90% confidence; we carry it through the calculation and show it as ±. Our margins treat the route-to-block-group split as exact, so the real uncertainty is larger. Routes with fewer than 100 estimated households, large margins, or streets we could not place are flagged.
Different years
USPS mailbox counts are current. Census figures are 5-year averages for 2020–2024, so a new subdivision may have more homes on the route today than the Census counted. Use the route figures to compare routes with each other, not as an exact head count.
Why some routes show identical figures
Two routes that run through the same block group get the same percentages and medians, because the Census publishes one set of figures for the whole block group. Their mailbox counts still differ, and those are exact.
Route and mailbox counts: USPS EDDM route data. Route demographics: EDDM2GO estimates from U.S. Census Bureau American Community Survey 5-year block-group data (2020–2024) and 2024 cartographic block-group boundaries. This product uses the Census Bureau Data API but is not endorsed or certified by the Census Bureau.
Nearby ZIP codes
- 21830 — Quantico CDP, MD (4.3 mi)
- 21861 — Sharptown town, MD (6 mi)
- 21659 — Galestown town, MD (8.5 mi)
- 21801 — Salisbury city, MD (8.7 mi)
- 21856 — Quantico CDP, MD (8.7 mi)
- 21869 — Vienna town, MD (9.4 mi)
- 21835 (10.7 mi)
- 19940 — Delmar town, DE (11 mi)
Areas that include 21837
- Mardela Springs, MD ZIP codes — 1 ZIP code
- Wicomico County ZIP codes — 16 ZIP codes
- Maryland ZIP code data
Where it ranks
- No. 3 of 11: highest share of owner-occupied homes in Wicomico County
- No. 5 of 11: highest median age in Wicomico County
Mail every home in 21837
Route counts on this page price as Full Service 6.5 × 9 postcards: we print, bundle by carrier route and hand the mailing to USPS. Prefer to take it to the Post Office yourself? Print only costs less and you pay postage at drop-off.
EDDM guides
ZIP code statistics describe the Census ZIP Code Tabulation Area (ZCTA) 21837, which approximates the USPS ZIP code area. Census figures: American Community Survey 5-year estimates, 2020–2024.
Frequently asked questions
- What city is 21837 in?
- 21837 is a Mardela Springs, MD mailing address. None of its land lies inside a Census-defined city or community.
- What county is 21837 in?
- 21837 is in Wicomico County.
- What is the population of 21837?
- About 2,891 people (±479), according to the Census Bureau's American Community Survey 5-year estimates for 2020–2024. The 2020 Census counted 2,647.
- What is the median household income in 21837?
- $62,880 (±$21,760), compared with $103,678 for Maryland as a whole. Half the households in the ZIP code earn more and half earn less.
- How many carrier routes and mailboxes are in 21837?
- 2 USPS carrier routes with 976 residential and 26 business mailboxes (1,003 in all), from the route data stored by EDDM2GO. An EDDM mailing can target any combination of these routes.
- What ZIP codes are near 21837?
- The closest, measured center to center: 21830 (4.3 mi, Quantico), 21861 (6 mi, Sharptown), 21659 (8.5 mi, Galestown), 21801 (8.7 mi, Salisbury), 21856 (8.7 mi, Quantico) and 21869 (9.4 mi, Vienna).
This product uses the Census Bureau Data API but is not endorsed or certified by the Census Bureau.