Postal Codes

21918 ZIP Code

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ZIP code 21918 covers Conowingo, Maryland, with a population of about 4,125 and a median household income of $81,026.

Population
4,125235 per square mile
Median age
41.73 points above the US average
Median household income
$81,02620% below the Maryland median
Poverty rate
5.2%7.2 points below the US average
Typical home value
$404,589up 22% in five years
Median rent
$1,00839% below the Maryland median
Degree or higher
14.5%20.5 points below the US average
Homeownership
88.4%23.4 points above the US average
Time zone
Eastern UTC-05:00observes daylight saving time
Businesses
49

Where 21918 is

Conowingo, Maryland — the area the Census Bureau draws for this ZIP code. ZIP codes are sets of delivery routes rather than areas, so this is the Census approximation of one, not a Postal Service boundary.

People and households

American Community Survey 2019–2023 five-year estimates

Population4,125
Median age41.7
Family households76.7%
Born outside the US0.4%
Speaks a language other than English at home4.9%
White (non-Hispanic)88.5%
Black (non-Hispanic)2.4%
Asian (non-Hispanic)0.4%
Hispanic or Latino1.8%
Veterans9%
Population by age
MaleFemale0-45-910-1415-1920-2425-3435-4445-5455-6465-7475-8485+
Income and poverty

American Community Survey 2019–2023 five-year estimates

Median household income$81,026
Income per person$40,778
Poverty rate5.2%
Households on SNAP or cash assistance6%

Household income distribution

Under $10k0.8%
$10–15k3.3%
$15–20k2.9%
$20–25k1.4%
$25–30k2.9%
$30–35k1.4%
$35–40k1.1%
$40–45k5.2%
$45–50k4.7%
$50–60k7.0%
$60–75k14.6%
$75–100k13.3%
$100–125k9.8%
$125–150k8.9%
$150–200k9.8%
$200k or more12.9%

Income as declared to the IRS

Filed returns rather than survey responses, so this counts tax units and not households.

Tax returns filed2,010
Mean adjusted gross income$75,283
Returns declaring $200,000 or more4%
Returns, under $25k23.9%
Returns, $25k–$50k21.4%
Returns, $50k–$75k15.4%
Returns, $75k–$100k12.4%
Returns, $100k–$200k22.9%
Returns, $200k or more4.0%
Housing

American Community Survey 2019–2023 five-year estimates

Median home value$293,800
Median gross rent$1,008
Owner-occupied88.4%
Vacant homes2.2%
Median year built1989

What the homes are

Detached house85.5%
2 to 4 units3.3%
Mobile home11.2%
Home values and rents today

Zillow Home Value Index and Zillow Observed Rent Index, courtesy of Zillow. Monthly and current, where the Census figures above are a five-year average and are capped at $2,000,000.

Typical home value$404,589as of 2026-07
Typical home value, 1 yearup 1.8%
Typical home value, 5 yearsup 22%
Typical home value, 10 yearsup 68.6%
Typical home value since 2000
200020132026$404,589$148,450

$148,450 in 2000 to $404,589 in 2026.

Work, commuting and education

American Community Survey 2019–2023 five-year estimates

Unemployment rate5.7%
Bachelor's degree or higher14.5%
High school diploma or higher90.4%
Works from home11.5%
Drives to work alone81%
Takes public transport0%
Commutes 45 minutes or more29.2%
Health

CDC PLACES 2025 release, model-based estimates. These are modelled small-area estimates for adults, not counts of diagnosed cases.

Obesity41.3% 7.9 pts above the national average of 33.4%
Diagnosed diabetes13.7% 1.7 pts above the national average of 12%
Currently smokes16.8% 3.6 pts above the national average of 13.2%
High blood pressure40.4% 6.3 pts above the national average of 34.1%
Fair or poor general health20.5% same as the national average of 20.3%
No health insurance (18–64)7.8% 3.5 pts below the national average of 11.3%
Depression23.9% 2 pts above the national average of 21.9%
No leisure-time physical activity28.5% 3.1 pts above the national average of 25.4%
Arthritis31.4% 6.3 pts above the national average of 25.1%
Binge drinking14.9% 1.1 pts below the national average of 16%
Taking blood pressure medication78.5% 3.8 pts above the national average of 74.7%
Cancer (non-skin)9.6% 1.9 pts above the national average of 7.7%
Current asthma10.7% same as the national average of 10.4%
Coronary heart disease7.2% 1 pts above the national average of 6.2%
Routine check-up in past year77.2% 0.5 pts above the national average of 76.7%
Cholesterol screening88% 2.1 pts above the national average of 85.9%
Cognitive disability14.8% same as the national average of 14.8%
Colorectal screening61.5% 2.8 pts below the national average of 64.3%
COPD8.7% 2.1 pts above the national average of 6.6%
Visited a dentist62.5% 1.2 pts above the national average of 61.3%
Any disability31.8% 1.1 pts above the national average of 30.7%
Lacks emotional support22% 2.8 pts below the national average of 24.8%
Food insecurity12.8% 4.3 pts below the national average of 17.1%
Received food stamps10.6% 3.7 pts below the national average of 14.3%
Hearing disability7.6% 0.9 pts above the national average of 6.7%
High cholesterol41% 4.8 pts above the national average of 36.2%
Housing insecurity10.7% 3.1 pts below the national average of 13.8%
Independent living disability8.2% same as the national average of 8.4%
Lacks transport7% 2.2 pts below the national average of 9.2%
Loneliness32.3% 2.1 pts below the national average of 34.4%
Mammography use69.8% 6.1 pts below the national average of 75.9%
Poor mental health (14+ days)17.9% 1.1 pts above the national average of 16.8%
Mobility disability14.8% 0.8 pts above the national average of 14%
Poor physical health (14+ days)15.1% 1.6 pts above the national average of 13.5%
Self-care disability3.9% same as the national average of 4%
Utility shut-off threat6.8% 2 pts below the national average of 8.8%
Sleeps under 7 hours38.3% 1.9 pts above the national average of 36.4%
Stroke3.8% same as the national average of 3.4%
All natural teeth lost11.5% 1.5 pts below the national average of 13%
Vision disability4.7% 0.9 pts below the national average of 5.6%
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Business and employment

Census ZIP Code Business Patterns 2022

Business establishments49
People employed257
Annual payroll$10,064,000
Natural hazard risk

FEMA National Risk Index, estimated for this ZIP code from census tract data — the NRI is not published per ZIP.

Overall riskHigher than 24.6% of US census tracts
FEMA ratingRelatively Low
Expected annual loss28.4 out of 100
Community resilience48.6 out of 100

By hazard

Score is out of 100 and is the area-weighted average across the census tracts this ZIP code covers. The rating beside it is the highest any one of those tracts carries.

Drought94.4Relatively Moderate at its worst in this ZIP code
Winter weather87.3Relatively High at its worst in this ZIP code
Landslide86.7Relatively Low at its worst in this ZIP code
Strong wind83.8Relatively High at its worst in this ZIP code
Hurricane70.3Relatively Low at its worst in this ZIP code
Heat wave64.4Relatively Moderate at its worst in this ZIP code
Coastal flooding61.7Relatively Low at its worst in this ZIP code
Ice storm61Relatively Moderate at its worst in this ZIP code
Lightning57.4Relatively Moderate at its worst in this ZIP code
Cold wave47.1Relatively Moderate at its worst in this ZIP code
Hail45.3Relatively Low at its worst in this ZIP code
Tornado43.9Relatively Low at its worst in this ZIP code
Earthquake40.9Relatively Low at its worst in this ZIP code
Wildfire38Very Low at its worst in this ZIP code
River flooding32.7Relatively Moderate at its worst in this ZIP code
Compared with Maryland and the United States

State and national columns are figures for those areas, not for this ZIP code. American Community Survey 2019–2023 five-year estimates

This ZIPMarylandUnited States
Median household income$81,026$101,652$78,538
Income per person$40,778$51,689$43,289
Poverty rate5.2%9.3%12.4%
Median home value$293,800$397,700$303,400
Median gross rent$1,008$1,662$1,348
Homeownership88.4%67.5%65%
Bachelor's degree or higher14.5%42.7%35%
Unemployment rate5.7%4.9%5.2%
Works from home11.5%17.2%13.5%
Born outside the US0.4%16.3%13.9%
Median age41.739.338.7
Climate

NOAA US Climate Normals 1991-2020, from the nearest weather station with a full year of records. The station and its distance are named above, because a station forty kilometres away describes somewhere else.

Weather stationCONOWINGO DAM, MD US2.9 km away
Rain in a year48 in

Average high and low by month

January40.1°F / 24.9°F3.63 in rain
February43°F / 26.3°F2.64 in rain
March51°F / 33.6°F4.18 in rain
April63.9°F / 43.8°F3.44 in rain
May73.5°F / 54°F3.86 in rain
June82.7°F / 64°F4.46 in rain
July87.5°F / 68.5°F4.69 in rain
August85.3°F / 67°F4.54 in rain
September78.8°F / 60°F5.05 in rain
October66.9°F / 47.9°F4.5 in rain
November55°F / 36.6°F3.23 in rain
December45°F / 30.6°F4.04 in rain
Access to food

USDA Food Access Research Atlas, estimated for this ZIP code from census tract data. Each figure is the share of the ZIP code's land area that falls in a tract carrying that flag.

Low income and far from a supermarket15% of this ZIP code's area
Far from a supermarket15% of this ZIP code's area
No vehicle and far from a supermarketNone of this ZIP code
School districts

NCES Geographic Relationship File 2025, which states the association between each district and each ZIP code tabulation area directly. Elementary and secondary districts can cover the same ground, so shares need not total 100%.

Cecil County Public Schools100% of this ZIP code's land area
Community and walkability

CDC/ATSDR Social Vulnerability Index 2022 and the EPA National Walkability Index, both estimated for this ZIP code from census tract data. Vulnerability figures are national percentile ranks, not measurements.

Overall social vulnerability32more vulnerable than 32% of US census tracts
Socioeconomic status40more vulnerable than 40% of US census tracts
Household characteristics26more vulnerable than 26% of US census tracts
Racial and ethnic minority status19more vulnerable than 19% of US census tracts
Housing type and transport43more vulnerable than 43% of US census tracts
Walkability5 out of 20Least walkable
Nearby ZIP codes

The closest ZIP codes by centre point, which is not the same as sharing a border.

21917 Colora, MD5.5 km away
21034 Darlington, MD6.6 km away
21911 Rising Sun, MD9.3 km away
17563 Peach Bottom, PA10.5 km away
21904 Port Deposit, MD10.6 km away
19362 Nottingham, PA12.7 km away
21160 Whiteford, MD14 km away
21078 Havre De Grace, MD14.4 km away
Location, counties and time zone

County shares from Census 2020 ZCTA relationship files. Time zone from the USDOT National Transportation Atlas, which renders the boundaries written into 49 CFR Part 71.

Cecil County100% of this ZIP code's land area
Time zoneEastern (UTC-05:00 standard)
Daylight saving timeObserved
Land area17.57 sq mi
Water area2.55 sq mi
Population density235 people per sq mi
Latitude, longitude39.6778, -76.1572

Figures are published for this ZIP code or its Census tabulation area unless a section says otherwise. Estimates whose margin of error made them unreliable are omitted rather than shown. Sources: US Census Bureau, CDC, IRS.

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