ZIP codes in Charles County
28 ZIPs touch Charles County, Maryland. The blue dashed line is the county border; orange ZIPs reach into it.
28
ZIP codes
5
cross the county line
226,013
people in these ZIPs
24
counties in MD
Most people
Charles County ZIP list
More counties in Maryland
- Baltimore County66
- Baltimore city50
- Calvert County15
- Caroline County11
- Carroll County16
- Cecil County17
- Dorchester County18
- Frederick County39
- Garrett County13
- Harford County25
- Howard County28
- Kent County9
Questions people actually ask
How many ZIP codes are in Charles County, Maryland?
28 ZIP codes reach into Charles County, including 3 PO Box or single-address ZIPs placed by the town they serve. 5 of them are only partly in the county and also cover a neighboring county.
Which ZIP code in Charles County has the most people?
20603 (Waldorf) has about 31,844 residents, the most of any ZIP touching Charles County, in the Census Bureau’s ACS 2020–2024 estimates.
Can a ZIP code be in Charles County and another county?
Yes. ZIP codes follow mail routes, not county lines. Rows marked with a percentage show how much of that ZIP’s land is in Charles County. For one address, pin the exact spot on the ZIP finder to see its county.
Where does this list come from?
ZIP areas and their county overlaps come from the Census Bureau’s 2020 ZIP Code Tabulation Area to county relationship file. PO Box ZIPs have no area, so each is placed in the county of the ZIP area nearest the town it serves.
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Updated 2026-11-10 · Where the data comes from