ZIP code 21778: Rocky Ridge, MD
21778 is a ZIP code in Rocky Ridge, Maryland, mainly in Frederick County, part of the Washington-Arlington-Alexandria, DC-VA-MD-WV metro area. About 745 people live here.
- Population
- 745
- Median household income
- $76,458
- Typical home value
- $440,100+0.4% in 12 months
- Median rent
- —gross, per month
- Median age
- 58.4
- Homeowners
- 81.3%of occupied homes
Shaded: ZIP code 21778's area. Click anywhere on the map to see which ZIP code it's in.
ZIP codes within 10 milesWithin 25 miles
ZIP code 21778 details
| City | Rocky Ridge |
|---|---|
| State | Maryland |
| County | Frederick County |
| Metro area | Washington-Arlington-Alexandria, DC-VA-MD-WV |
| Time zone | Eastern Time (UTC−5), observes daylight saving time |
| Type | Standard (delivery area) |
| Land area | 18.2 sq mi, plus 0.4 sq mi of water |
| Population density | 41 people per sq mi |
| Bachelor's degree or higher | 27% of adults 25+ |
| Average commute | 26 minutes |
| Center coordinates | 39.61581, -77.32842 |
ZIP codes near 21778
| ZIP code | City | Distance | Population |
|---|---|---|---|
| 21759 | Ladiesburg, MD | 3.8 mi | — |
| 21775 | New Midway, MD | 4.0 mi | — |
| 21757 | Keymar, MD | 4.0 mi | 2,671 |
| 21788 | Thurmont, MD | 4.9 mi | 11,654 |
| 21727 | Emmitsburg, MD | 5.0 mi | 6,052 |
| 21798 | Woodsboro, MD | 5.7 mi | 2,928 |
| 21780 | Sabillasville, MD | 8.6 mi | 2,159 |
| 21793 | Walkersville, MD | 8.8 mi | 10,719 |
Population and median household income: ACS 2020–2024 5-year estimates. Typical home value: Zillow Home Value Index (September 2026) where available, otherwise the ACS median owner-reported value. "PO Box" marks ZIP codes with no delivery area of their own. Methodology
Buying a home in 21778?
A typical home in ZIP code 21778 is worth about $440,100 (Zillow Home Value Index). The median household here earns $76,458 a year. See what buying here would cost per month, with Maryland average taxes and insurance filled in.
Monthly payment for a $440,100 homeWhat can a $76,458 income afford?Rental property numbers
About ZIP code 21778
What city is ZIP code 21778?
ZIP code 21778 is in Rocky Ridge, MD, in Frederick County.
What county is ZIP code 21778 in?
21778 is mainly in Frederick County, Maryland.
What is the population of ZIP code 21778?
About 745 people live in ZIP code 21778, according to the American Community Survey 2020–2024 5-year estimates.
What time zone is ZIP code 21778 in?
21778 is in Eastern Time (UTC−5). It observes daylight saving time.