| Town | 2010 | 2020 | Change | Change, % | |
|---|---|---|---|---|---|
| 1 | Andover | 3,303 | 3,151 | −152 | −4.6% |
| 2 | Ansonia | 19,249 | 18,918 | −331 | −1.7% |
| 3 | Ashford | 4,317 | 4,191 | −126 | −2.9% |
| 4 | Avon | 18,098 | 18,932 | 834 | 4.6% |
| 5 | Barkhamsted | 3,799 | 3,647 | −152 | −4.0% |
| 6 | Beacon Falls | 6,049 | 6,000 | −49 | −0.8% |
| 7 | Berlin | 19,866 | 20,175 | 309 | 1.6% |
| 8 | Bethany | 5,563 | 5,297 | −266 | −4.8% |
| 9 | Bethel | 18,584 | 20,358 | 1,774 | 9.6% |
| 10 | Bethlehem | 3,607 | 3,385 | −222 | −6.2% |
