21128 ZIP Code, Perry Hall, MD

21128 is a ZIP code in Perry Hall, Maryland in Baltimore County. It covers 6.8 square miles of land. The closest ZIP codes are 21236, 21162 and 21156. 15,501 people live here in 5,609 households. At about 2,277 people per square mile it has suburban density, and most homes are owner-occupied (84%). Median household income is $128,069, above the Maryland median of $103,678.

Quick facts

Key figures

MeasureValue
Residents15,501
Households5,609
Median household income$128,069
Income per person$54,499
Median age40.1
Homeowners84.0%
Median home value$449,500
Median rent$1,935
Bachelor's degree or higher54.8%
Average commute (minutes)33.2
Households with kids under 1829.6%
Moved in the past year5.7%
Below the poverty line3.1%
Broadband internet95.4%
Speak a non-English language at home24.1%

Household income

% of householdsValue
<$10K2.2%
$10–15K2.5%
$15–25K2.0%
$25–35K6.5%
$35–50K4.0%
$50–75K10.5%
$75–100K7.9%
$100–150K24.4%
$150–200K13.9%
$200K+26.2%

Age

% of all residentsValue
<1011.2%
10–1912.6%
20–246.7%
25–3412.2%
35–4412.7%
45–5414.1%
55–6413.0%
65–749.9%
75+7.6%

Tenure

% of housing unitsValue
Owned, with mortgage51.7%
Owned outright28.1%
Rented15.0%
Vacant5.1%

Type of building

% of housing unitsValue
Detached house59.2%
Townhome16.6%
2–4 units0.0%
5–19 units19.7%
20+ units4.5%
Mobile / other0.0%

Businesses in 21128

223 business establishments with 2,023 employees (ZIP Codes Business Patterns 2023).

EDDM carrier routes

21128 has 10 USPS carrier routes with 6,193 residential and 96 business mailboxes. Open the EDDM route map.

Carrier routes in 21128

21128 has 10 USPS carrier routes (10 rural (R)) with 6,193 residential and 96 business mailboxes. Routes range from 395 homes (R650) to 737 homes (R659); the median route has 633 homes. The Census counted 5,609 households in 21128 (2020–2024 average); USPS counts current mailboxes, including new and vacant homes.

Homes per routeRoutes
1–2490
250–4991
500–7499
750–9990
1,000–1,4990
1,500+0

Best routes in 21128 for…

Most businesses

For B2B offers: office supplies, cleaning, IT, catering and commercial services.

  1. Route R657 — USPS business mailboxes 39, 642 homes
  2. Route R651 — USPS business mailboxes 19, 677 homes
  3. Route R658 — USPS business mailboxes 14, 607 homes
  4. Route R652 — USPS business mailboxes 8, 628 homes
  5. Route R654 — USPS business mailboxes 7, 703 homes

Select these 5 routes on the route map

Every carrier route in 21128

RouteTypeHomesBusinessesEst. median incomeEst. ownersEst. families with kidsEst. moved in past year
R650Rural3951$167,506———
R651Rural67719$103,209———
R652Rural6288$104,510———
R653Rural6385$90,668———
R654Rural7037$90,668———
R655Rural5720$104,510———
R656Rural5940$75,857———
R657Rural64239$110,744———
R658Rural60714$167,506———
R659Rural7373$90,668———

Income, owners, families and movers are estimates for each route (how we estimate them); mailbox counts are current USPS figures. Open 21128 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

Areas that include 21128

Where it ranks

Mail every home in 21128

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) 21128, which approximates the USPS ZIP code area. Census figures: American Community Survey 5-year estimates, 2020–2024.

Frequently asked questions

What city is 21128 in?
21128 is a Perry Hall, MD mailing address. By land area, 51% lies inside Honeygo, 31% lies inside White Marsh and 18% lies inside Perry Hall.
What county is 21128 in?
21128 is in Baltimore County.
What is the population of 21128?
About 15,501 people (±1,347), according to the Census Bureau's American Community Survey 5-year estimates for 2020–2024. The 2020 Census counted 14,861.
What is the median household income in 21128?
$128,069 (±$11,538), 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 21128?
10 USPS carrier routes with 6,193 residential and 96 business mailboxes (6,290 in all), from the route data stored by EDDM2GO. An EDDM mailing can target any combination of these routes.
What ZIP codes are near 21128?
The closest, measured center to center: 21236 (2.2 mi, Perry Hall), 21162 (2.5 mi, Honeygo), 21156 (2.9 mi, Kingsville), 21087 (3.6 mi, Kingsville), 21234 (4.5 mi, Carney) and 21057 (4.6 mi, Carney).

This product uses the Census Bureau Data API but is not endorsed or certified by the Census Bureau.