5 cities
| City | County | 2026 Pop. ↓ |
|---|---|---|
| Trumbull | Greater Bridgeport Planning Region | 39,015 |
| Torrington | Northwest Hills Planning Region | 35,828 |
| Tolland | Capitol Planning Region | 14,907 |
| Thompson | Northeastern CT Planning Region | 9,743 |
| Thomaston | Naugatuck Valley Planning Region | 7,634 |