| City: | Riderwood, Maryland |
| County: | Baltimore County |
| Timezone: | Eastern (GMT -05:00) |
| Local Time: | 9:59:11 PM |
| Population: | No Population Data |
| Area Codes: | 410 / 443 / 667 |
| Classification: | PO Box |
| Coordinates: | 39.4095, -76.6487 |
| Quick Link: |
The facility's setup reflects the area's character as a small service point within the greater Baltimore suburban network. Located between established neighborhoods like Ruxton, Pikesville, and Lutherville-Timonium, the post office maintains 134 business records and 62 ZIP+4 codes. The single street in the delivery system, Bellona Avenue, accounts for 42 delivery records with unit designations. This configuration suggests a compact service area where the post office functions more as a mail sorting point than a standalone community hub.
The delivery system centers entirely on Bellona Avenue, which accounts for all 42 street delivery records in the ZIP code. This single-street configuration is unusual and suggests the ZIP primarily functions as a PO Box facility rather than a full-service post office with extensive street delivery territory.
ZIP Code 21139 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: | 3,315Source: 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 21139 is located in Baltimore County, Maryland, within the Baltimore-Columbia-Towson, MD Metropolitan Statistical Area (CBSA 12580) and Maryland's 2nd Congressional District. This Metro area has a population of 2,710,489 people, about 0.00% of whom live in ZIP Code 21139. It covers 0 sq mi of land and a water area of 0 sq mi.
| CBSA Name: | Baltimore-Columbia-Towson, MDSource: Census |
| CBSA Number: | 12580Source: Census |
| CBSA Type: | MetroSource: Census |
| CBSA Division: | --Source: Census |
| CBSA Population: | 2,710,489Source: Census |
| MSA: | Washington-Baltimore, DC-MD-VA-WV CMSASource: Census |
| Land Area: | --Source: Census |
| Water Area: | --Source: Census |
| Congressional District: | 02Source: USPS |
| Congressional Land Area: | 348.88 sq miSource: Census |
| PMSA: | Baltimore, MD 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 21139 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.