43 zips
| Zip Code | City | Population ↓ |
|---|---|---|
| 22030 | Fairfax | 61,665 |
| 22003 | Annandale | 58,872 |
| 20171 | Herndon | 51,081 |
| 22015 | Burke | 44,959 |
| 20170 | Herndon | 43,557 |
| 20120 | Centreville | 43,315 |
| 22033 | Fairfax | 38,610 |
| 22079 | Lorton | 36,857 |
| 22309 | Alexandria | 36,265 |
| 22031 | Fairfax | 35,872 |
| 22042 | Falls Church | 34,860 |
| 22306 | Alexandria | 32,842 |
| 22153 | Springfield | 32,546 |
| 22101 | McLean | 30,729 |
| 22152 | Springfield | 30,155 |
| 22310 | Alexandria | 29,788 |
| 20191 | Reston | 29,758 |
| 22032 | Fairfax | 29,510 |
| 22315 | Alexandria | 29,358 |
| 22041 | Falls Church | 29,132 |
| 22102 | McLean | 28,356 |
| 22150 | Springfield | 27,734 |
| 20121 | Centreville | 27,428 |
| 22182 | Vienna | 26,892 |
| 22312 | Alexandria | 26,573 |
| 22180 | Vienna | 26,179 |
| 22043 | Falls Church | 25,843 |
| 20151 | Chantilly | 21,893 |
| 20190 | Reston | 21,121 |
| 22124 | Oakton | 18,449 |
| 22039 | Fairfax Station | 17,624 |
| 22066 | Great Falls | 16,925 |
| 22151 | Springfield | 16,827 |
| 22303 | Alexandria | 16,321 |
| 22181 | Vienna | 15,698 |
| 20124 | Clifton | 15,117 |
| 22044 | Falls Church | 14,042 |
| 22308 | Alexandria | 12,980 |
| 20194 | Reston | 12,576 |
| 22307 | Alexandria | 10,202 |
| 22060 | Fort Belvoir | 9,846 |
| 22027 | Dunn Loring | 1,974 |
| 22035 | Fairfax | 0 |
The data shown reflect ZCTAs from the US Census. As of 2024, there are 43 ZCTAs in Fairfax County, Virginia (US Census).