ZIP code · Monrovia · Maryland · United States
ZIP code 21770 — Monrovia
ZIP code 21770 serves Monrovia, Maryland.
- Postal code
- 21770Single source Value from one source, not cross-checked.
- City
- Monrovia
- County
- Frederick
- State
- Maryland
- Country
- United States
- Coordinates
- 39.3512, -77.2494 — precision precise (locality)
View on OpenStreetMap - Population
- 7,815 (ZCTA, ACS 5-year)
- Median household income
- $184,464
- Median age
- 41.2
- Time zone
- America/New_York (UTC−5 / UTC−4 DST)
- Area codes
- 240, 301 (from the nearest rate centre)Telephone area codes serving this ZIP (NANPA central-office assignments). A ZIP and an area code are different boundaries; at a border both codes may apply.
About this page
US ZIP codes have five digits. They are postal routing areas, not administrative boundaries: a ZIP can span more than one city or county, and the city shown is the primary USPS name for that code.
GeoNames · U.S. Census Bureau (ACS). Data generated on 2026-08-21. Methodology · Report an error on this page