Zip Code 21042 — Ellicott City, MD
21042 is a ZIP Code associated with Ellicott City, MD, located within Howard. 21042 ranks #3 out of 20 ZIP codes in Howard County by population (and #32 out of 477 in MD). The area supports an estimated population of 43,327 residents across Data Pending housing units, with a population density of 452.1 people per square mile.
WorldPlaceData database updated: October 2026
📍 View location on OpenStreetMap (39.271050, -76.892400)
| Data Metric | Local Statistic |
|---|
| Postal / Zip Code | 21042 |
| Primary City | Ellicott City |
| State / Province | MD |
| County | Howard |
| Total Population | 43,327 |
| Median Household Income | Data Pending |
| Total Housing Units | Data Pending |
| Population Density | 452.1 people/sq mi |
| Timezone | America/New_York |
How 21042 Compares
| Metric | ZIP 21042 | Howard County | MD State Average |
|---|
| Population | 43,327 | 335,512 (Total) | 6,205,597 (Total) |
| Average ZIP Income | Data Pending | N/A | N/A |
| Population Density | 452.1 /sq mi | -- | -- |
| County Pop Rank | #3 of 20 | -- | -- |
Nearby ZIP Codes
Data Sources & Methodology: Geographic coordinates and ZIP Code assignments are derived from underlying geographic and postal datasets. Note that ZIP Codes are USPS postal delivery areas, while Census ZCTAs are statistical approximation areas. Read full methodology →