ZIP Codes in Gaithersburg, MD
Gaithersburg uses 5 ZIP codes, all in Montgomery County. Pick one below for details, or look up the full nine-digit ZIP+4 for a specific street address.
All 5 Gaithersburg ZIP codes
| ZIP | Type | County | Population |
|---|---|---|---|
| 20877 | standard | Montgomery | 38,546 |
| 20878 | standard | Montgomery | 66,115 |
| 20879 | standard | Montgomery | 25,264 |
| 20882 | standard | Montgomery | 13,751 |
| 20899 | standard | Montgomery | 57 |
Finding a ZIP+4 in Gaithersburg
Knowing which of these 5 ZIP codes covers an address only gets you partway. The four-digit extension identifies the specific delivery point — typically one side of one block. Two houses facing each other on the same Gaithersburg street almost always have different ZIP+4 codes even though they share all five leading digits.
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