Fastest Growing Counties in Delaware (2026)

County
Rank
Change (2020)
2026 Pop.
2020 Pop.
Sussex County118.61%283,047238,627
Kent County27.88%196,696182,322
New Castle County33.34%590,038570,941

Delaware Counties Growth Overview

Delaware's counties show varied growth patterns from 2020 to 2026. Sussex County leads with 2.89% annualized growth, followed by Kent County (1.27%) and New Castle County (0.55%). The largest counties are New Castle County (590,038), Sussex County (283,047), and Kent County (196,696). All 3 counties in Delaware are growing. Overall, counties averaged 1.57% annualized growth, with total population growing by 1.27% annually.

Change (2020)

-0.05

-0.025

0

0.025

0.05

0.075