ZIP code 21778
Where is ZIP code 21778?
Rocky Ridge, Maryland
Frederick County · Standard ZIP code
ZIP code 21778 belongs to Rocky Ridge, Maryland in Frederick County. 21778 is a standard ZIP code, so it covers street addresses as well as PO Boxes. It is in the Eastern Time zone and uses area codes 227, 240, 301, 410, 443 and 667. About 745 people live in the 21778 area, where the median household income is $76,458. The closest ZIP codes are 21759 (Ladiesburg, 3.3 mi southeast), 21775 (New Midway, 3.4 mi southeast) and 21788 (Thurmont, 3.7 mi west).
| ZIP code | 21778 |
|---|---|
| Type | Standard ZIP code for street addresses and PO Boxes |
| Status | Active |
| City | Rocky Ridge |
| State | Maryland (MD) |
| County | Frederick County |
| Time zone | Eastern Time · now |
| Area codes | 227, 240, 301, 410, 443, 667 |
| Coordinates | 39.6057, -77.3296 map |
| 3-digit prefix | 217 |
Population and income in 21778
| Population | 745 · lower than 78% of Maryland ZIP codes |
|---|---|
| People per square mile | 41 · lower than 91% of Maryland ZIP codes |
| Median age | 58.4 years · higher than 91% of Maryland ZIP codes |
| Men / women | 39% / 61% |
| Median household income | $76,458 · lower than 81% of Maryland ZIP codes |
| Income per person | $54,798 |
| Below the poverty line | 0.9% |
| Bachelor’s degree or higher | 27% of adults 25+ |
| Median home value | $382,100 · lower than 59% of Maryland ZIP codes |
| Housing units | 332 |
| Households | 332 (2.24 people on average) |
| Owners / renters | 81% / 19% |
| Land area | 18.24 sq mi (plus 0.37 sq mi of water) |
Source: U.S. Census Bureau, American Community Survey 5-year estimates (2020–2024) for ZIP Code Tabulation Area 21778. Census ZIP areas are close to, but not exactly the same as, USPS delivery areas.
ZIP codes near 21778
| ZIP code | City | Distance | Type |
|---|---|---|---|
| 21759 | Ladiesburg, MD | 3.3 mi SE | PO Box only |
| 21775 | New Midway, MD | 3.4 mi SE | PO Box only |
| 21788 | Thurmont, MD | 3.7 mi W | Standard |
| 21757 | Keymar, MD | 3.8 mi SE | Standard |
| 21798 | Woodsboro, MD | 5.4 mi S | Standard |
| 21727 | Emmitsburg, MD | 6.1 mi N | Standard |
| 21793 | Walkersville, MD | 8.8 mi S | Standard |
| 21780 | Sabillasville, MD | 9.1 mi NW | Standard |
| 21787 | Taneytown, MD | 9.5 mi NE | Standard |
| 21762 | Libertytown, MD | 9.6 mi SE | PO Box only |
| 21709 | Frederick, MD | 9.9 mi S | Unique |
| 21702 | Frederick, MD | 10.5 mi SW | Standard |
Straight-line distance between ZIP code center points. Find every ZIP code within 10 miles of 21778 or measure the distance to another ZIP code.
How to address mail to 21778
123 MAIN ST
ROCKY RIDGE MD 21778
Put the city, the two-letter state code and the ZIP code on the last line. Adding the 4-digit ZIP+4 code (21778-XXXX) helps mail sort faster but isn’t required.
Questions
- What city is ZIP code 21778?
- 21778 is a Rocky Ridge, Maryland ZIP code.
- What county is 21778 in?
- ZIP code 21778 is in Frederick County, Maryland.
- What time zone is ZIP code 21778 in?
- 21778 is in the Eastern Time zone (America/New_York).
- What area code is 21778?
- Phone numbers in ZIP code 21778 use area codes 227, 240, 301, 410, 443 and 667.
- What is the population of ZIP code 21778?
- About 745 people live in ZIP code 21778, according to the Census Bureau’s American Community Survey (2020–2024).
- What is the median income in 21778?
- The median household income in 21778 is $76,458 a year, lower than 81% of Maryland ZIP codes.
- What ZIP codes are near 21778?
- The nearest ZIP codes to 21778 are 21759 (Ladiesburg, 3.3 miles), 21775 (New Midway, 3.4 miles), 21788 (Thurmont, 3.7 miles) and 21757 (Keymar, 3.8 miles).