Fairfield County Cities Listed by Area Code 203
| Area Code | City | State | Zip Code |
| 203 | Bethel | CT | 06801 |
| 203 | Bridgeport | CT | 06604 |
| 203 | Brookfield | CT | 06804 |
| 203 | Cos Cob | CT | 06807 |
| 203 | Danbury | CT | 06810 |
| 203 | Darien | CT | 06820 |
| 203 | Easton | CT | 06612 |
| 203 | Fairfield | CT | 06430 |
| 203 | Greenwich | CT | 06830 |
| 203 | Monroe | CT | 06468 |
| 203 | New Canaan | CT | 06840 |
| 203 | New Fairfield | CT | 06812 |
| 203 | Newtown | CT | 06470 |
| 203 | Norwalk | CT | 06850 |
| 203 | Old Greenwich | CT | 06870 |
| 203 | Redding | CT | 06896 |
| 203 | Ridgefield | CT | 06877 |
| 203 | Riverside | CT | 06878 |
| 203 | Sandy Hook | CT | 06482 |
| 203 | Shelton | CT | 06484 |
| 203 | Southport | CT | 06490 |
| 203 | Stamford | CT | 06901 |
| 203 | Stratford | CT | 06614 |
| 203 | Trumbull | CT | 06611 |
| 203 | Weston | CT | 06883 |
| 203 | Westport | CT | 06880 |
| 203 | Wilton | CT | 06897 |