| City: | Waldorf, Maryland |
| City Alias: | Saint Charles |
| County: | Charles County |
| Timezone: | Eastern (GMT -05:00) |
| Local Time: | 2:12:41 AM |
| Population: | No Population Data |
| Area Codes: | 227 / 240 / 301 |
| Classification: | PO Box |
| Coordinates: | 38.6247, -76.9395 |
| Quick Link: |
ZIP code 20604 serves Waldorf, Maryland, a fast-growing community in Charles County about 25 miles south of Washington, DC. This isn't a town unto itself. It's a PO Box facility located within the larger Waldorf area, which is covered by standard ZIP 20603.
The post office maintains 594 PO Boxes and serves 351 businesses. With zero residential population counted in Census data, this ZIP exists purely as a postal access point. It doesn't define a neighborhood or territory. Residents who use a 20604 address live within the boundaries of 20603, picking up mail at this secondary facility.
Mail addressed to either "Waldorf" or "Saint Charles" can use 20604. The St. Charles alias dates back before 2004, referencing the large planned community of St. Charles that shaped this area's development. Street delivery exists but routes through a single address: Post Office Road, where the facility itself sits.
For practical purposes, 20604 offers an alternative to the main Waldorf post office. Businesses and residents choose it for shorter lines, convenience, or preference. It's part of the Washington, DC metropolitan area's suburban postal infrastructure, serving a community that has grown dramatically since the 1970s.
The only street in this ZIP is Post Office Road, the location of the PO Box facility itself.
ZIP Code 20604 supports both business and residential activity. According to the Business Census (2024), there are 16 business establishments, employing about 148 people with an annual payroll of $6,215,000.
| # Residential Mailboxes: | 0Source: USPS |
| # Business Mailboxes: | 0Source: USPS |
| Total Delivery Receptacles: | 5,087Source: USPS |
| Single Family Delivery Units: | 0Source: USPS |
| Multi Family Delivery Units: | 0Source: USPS |
| # of Businesses: | 16Source: CBP |
| 1st Quarter Payroll: | $1,454,000Source: CBP |
| Annual Payroll: | $6,215,000Source: CBP |
| # of Employees: | 148Source: CBP |
ZIP Code 20604 is located in Charles County, Maryland, within the Washington-Arlington-Alexandria, DC-VA-MD-WV Metropolitan Statistical Area (CBSA 47900) and Maryland's 5th Congressional District. This Metro area has a population of 6,263,796 people, about 0.00% of whom live in ZIP Code 20604, and is subdivided into the Washington, DC-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: | Washington, DC-MD (CBSA Div 47764)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: | 05Source: USPS |
| Congressional Land Area: | 1481.24 sq miSource: Census |
| PMSA: | Washington, DC-MD-VA-WV PMSASource: Census |
| Intro Date: | < 2004-10Source: ZIP-Codes.com |
| Place FIPS Code: | 2481175Source: Census |
| Place Name: | Waldorf CDP; MarylandSource: Census |
We could not locate which school district 20604 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.