Fastest Growing Counties in Connecticut (2025)

County
Rank
Change (2020)
2025 Pop.
2020 Pop.
Northeastern CT Planning Region12.69%97,78095,222
Naugatuck Valley Planning Region22.65%461,204449,285
Capitol Planning Region32.02%981,848962,436
Lower CT River Valley Planning Region41.97%176,681173,268
Northwest Hills Planning Region51.46%113,835112,202
Greater Bridgeport Planning Region61.33%328,703324,387
Western CT Planning Region71.24%626,007618,368
Southeastern CT Planning Region80.74%280,388278,342
South Central CT Planning Region90.64%567,670564,076

Connecticut County Growth Overview

Connecticut's counties show varied growth patterns from 2020 to 2025. Northeastern CT Planning Region leads with 2.69% annualized growth, followed by Naugatuck Valley Planning Region (2.65%) and Capitol Planning Region (2.02%). The largest counties are Capitol Planning Region (981,848), Western CT Planning Region (626,007), and South Central CT Planning Region (567,670). All 9 counties in Connecticut are growing. Overall, counties averaged 1.64% annualized growth, with total population growing by 1.58% annually.