ZIP Code 21778 – Rocky Ridge, MD
Rocky Ridge, Maryland · Frederick County · Eastern time
| ZIP code | 21778 |
|---|---|
| City | Rocky Ridge |
| State | Maryland |
| County | Frederick County |
| Population | 745 |
| Time zone | Eastern · local time |
| ZIP type | Standard (has a Census ZCTA area) |
| Land area | 18.24 sq mi |
| Center (lat, long) | 39.6158, -77.3284 |
Area codes in this area
These are the area codes that most often serve ZIP 21778 (including overlays). The exact area code depends on the phone number — landlines, mobiles and overlays can differ even on the same street.
Map
Nearby ZIP codes
About ZIP 21778
ZIP code 21778 is assigned to Rocky Ridge, Maryland. It lies in Frederick County. Its Census area covers about 18.24 square miles of land. The closest neighboring ZIP is 21759 (Ladiesburg), about 3.8 miles away.
Every address in 21778 also has a 4-digit add-on code (ZIP+4) that points to a smaller delivery area. Use the box above to find it.
Sources: US Census Bureau (ZCTA, county relationship files), GeoNames (CC BY 4.0), NANPA via NumberResearch.org (CC BY 4.0). Map © OpenStreetMap contributors. ZIP areas are approximate. Population: U.S. Census Bureau, ACS 5-year estimates, 2024 (ZCTA). Data sources