| City: | Unionville, Maryland |
| County: | Frederick County |
| Timezone: | Eastern (GMT -05:00) |
| Local Time: | 10:02:51 PM |
| Population: | No Population Data |
| Area Codes: | 227 / 240 / 301 |
| Classification: | PO Box |
| Coordinates: | 39.4748, -77.1859 |
| Quick Link: |
Unionville, Maryland (21792) is a PO Box-classified ZIP code in Frederick County with an unusual postal setup. Despite carrying PO Box classification dating to before October 2004, this ZIP maintains no actual PO Boxes and serves zero residential population within its Census boundaries.
The ZIP operates as a point location rather than a defined service area, enclosed within the larger 21771 ZIP code. Mail delivery here uses a single rural carrier route (R001) serving Unionville Road. The only named building in the ZIP+4 database is the United States Postal Service facility itself, suggesting this is primarily an administrative designation.
Unionville isn't a PO Box Only Zone, meaning street delivery is available in the area through neighboring ZIP codes. The classification appears to be legacy postal infrastructure rather than an active community service point.
Only one street (Unionville Road) appears in the ZIP+4 database with 2 delivery records.
ZIP Code 21792 is designated for PO Box delivery only; business establishment and employment data are not available.
| # Residential Mailboxes: | 0Source: USPS |
| # Business Mailboxes: | 0Source: USPS |
| Total Delivery Receptacles: | 19Source: USPS |
| Single Family Delivery Units: | 0Source: USPS |
| Multi Family Delivery Units: | 0Source: USPS |
| # of Businesses: | 0Source: CBP |
| 1st Quarter Payroll: | $0Source: CBP |
| Annual Payroll: | $0Source: CBP |
| # of Employees: | 0Source: CBP |
ZIP Code 21792 is located in Frederick County, Maryland, within the Washington-Arlington-Alexandria, DC-VA-MD-WV Metropolitan Statistical Area (CBSA 47900) and Maryland's 6th Congressional District. This Metro area has a population of 5,582,170 people, about 0.00% of whom live in ZIP Code 21792, and is subdivided into the Frederick-Gaithersburg-Bethesda, MD division. It covers 0 sq mi of land and a water area of 0 sq mi.
| CBSA Name: | Washington-Arlington-Alexandria, DC-VA-MD-WVSource: Census |
| CBSA Number: | 47900Source: Census |
| CBSA Type: | MetroSource: Census |
| CBSA Division: | Frederick-Gaithersburg-Bethesda, MD (CBSA Div 23224)Source: Census |
| CBSA Population: | 5,582,170Source: Census |
| MSA: | Washington-Baltimore, DC-MD-VA-WV CMSASource: Census |
| Land Area: | --Source: Census |
| Water Area: | --Source: Census |
| Congressional District: | 06Source: USPS |
| Congressional Land Area: | 1950.26 sq miSource: Census |
| PMSA: | Washington, DC-MD-VA-WV PMSASource: Census |
| Intro Date: | < 2004-10Source: ZIP-Codes.com |
| Place FIPS Code: | --Source: Census |
| Place Name: | --Source: Census |
We could not locate which school district 21792 belongs to, but we will update this once new district data is released. There are no public schools nor private schools with a mailing address in this ZIP Code. Listing Nearby schools instead. It also has 6 colleges, universities or post secondary education institutions nearby which would be a short commute to.
Our sources include trusted federal and licensed data from the United States Postal Service, U.S. Census Bureau, U.S. Geological Survey, Centers for Medicare & Medicaid Services, and the National Center for Education Statistics, along with proprietary datasets created by ZIP-Codes.com. Data last updated on February 1, 2026.