43 zips
| Zip Code | City | Population ↓ |
|---|---|---|
| 22030 | Fairfax | 60,855 |
| 22003 | Annandale | 58,154 |
| 20171 | Herndon | 50,796 |
| 22015 | Burke | 44,730 |
| 20170 | Herndon | 43,372 |
| 20120 | Centreville | 42,917 |
| 22033 | Fairfax | 38,676 |
| 22031 | Fairfax | 36,586 |
| 22079 | Lorton | 36,523 |
| 22309 | Alexandria | 34,948 |
| 22042 | Falls Church | 34,631 |
| 22153 | Springfield | 32,656 |
| 22306 | Alexandria | 31,471 |
| 22101 | McLean | 31,306 |
| 20191 | Reston | 30,077 |
| 22041 | Falls Church | 29,764 |
| 22032 | Fairfax | 29,172 |
| 22310 | Alexandria | 29,120 |
| 22152 | Springfield | 29,066 |
| 22315 | Alexandria | 28,725 |
| 22102 | McLean | 28,577 |
| 22150 | Springfield | 27,770 |
| 22182 | Vienna | 27,592 |
| 20121 | Centreville | 27,507 |
| 22180 | Vienna | 26,506 |
| 22312 | Alexandria | 26,366 |
| 22043 | Falls Church | 25,658 |
| 20151 | Chantilly | 22,502 |
| 20190 | Reston | 22,092 |
| 22039 | Fairfax Station | 19,034 |
| 22124 | Oakton | 18,915 |
| 22151 | Springfield | 17,376 |
| 22066 | Great Falls | 16,884 |
| 22303 | Alexandria | 16,566 |
| 22181 | Vienna | 15,529 |
| 20124 | Clifton | 14,557 |
| 22044 | Falls Church | 14,001 |
| 22308 | Alexandria | 13,660 |
| 20194 | Reston | 12,334 |
| 22060 | Fort Belvoir | 10,261 |
| 22307 | Alexandria | 10,205 |
| 22027 | Dunn Loring | 1,781 |
| 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).