| City: | Potomac, Maryland |
| City Alias: | Rockville |
| County: | Montgomery County |
| Timezone: | Eastern (GMT -05:00) |
| Local Time: | 2:18:36 AM |
| Population: | No Population Data |
| Area Codes: | 227 / 301 |
| Classification: | PO Box |
| Coordinates: | 39.0183, -77.2089 |
| Quick Link: |
Mail addressed to 20859 goes exclusively to PO Boxes at the Potomac post office facility. Street addresses in the surrounding area use neighboring ZIP code 20854 for standard delivery. The single street associated with this ZIP—River Road—contains 90 postal records with unit designations, but these reference the broader Potomac community rather than a distinct neighborhood. Potomac residents and businesses choose this facility for mail security, package holding, or business correspondence needs that benefit from a dedicated box rather than home delivery.
Only one street name appears in postal records: River Road, with 90 delivery points that include unit designations. This reflects the facility's role as a PO Box service point rather than a street delivery hub.
ZIP Code 20859 supports both business and residential activity. According to the Business Census (2024), there are 11 business establishments, employing about 101 people with an annual payroll of $3,938,000.
| # Residential Mailboxes: | 0Source: USPS |
| # Business Mailboxes: | 0Source: USPS |
| Total Delivery Receptacles: | 510Source: USPS |
| Single Family Delivery Units: | 0Source: USPS |
| Multi Family Delivery Units: | 0Source: USPS |
| # of Businesses: | 11Source: CBP |
| 1st Quarter Payroll: | $939,000Source: CBP |
| Annual Payroll: | $3,938,000Source: CBP |
| # of Employees: | 101Source: CBP |
ZIP Code 20859 is located in Montgomery County, Maryland, within the Washington-Arlington-Alexandria, DC-VA-MD-WV Metropolitan Statistical Area (CBSA 47900) and Maryland's 8th Congressional District. This Metro area has a population of 6,263,796 people, about 0.00% of whom live in ZIP Code 20859, 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: | 6,263,796Source: Census |
| MSA: | Washington-Baltimore, DC-MD-VA-WV CMSASource: Census |
| Land Area: | --Source: Census |
| Water Area: | --Source: Census |
| Congressional District: | 08Source: USPS |
| Congressional Land Area: | 859.85 sq miSource: Census |
| PMSA: | Washington, DC-MD-VA-WV PMSASource: Census |
| Intro Date: | < 2004-10Source: ZIP-Codes.com |
| Place FIPS Code: | 2463300Source: Census |
| Place Name: | Potomac CDP; MarylandSource: Census |
We could not locate which school district 20859 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 January 1, 2026.