Delaware Counties by Population (2025)

Top 5 Most Populous Counties

3 Counties

County
2025 Pop.
Area (mi²)
Density
Change (2020)
New Castle County585,2684261,3742.51%
Sussex County277,63393629716.35%
Kent County193,8515863316.33%

Overview of Delaware Delaware Counties

Sources

  1. US Census State Population Estimates - Most recent state estimates from the Census Bureau's Population Estimates Program
  2. US Census County Population Estimates - Most recent county estimates from the Census Bureau's Population Estimates Program
  3. American Community Survey (2009 - 2013)
  4. Census QuickFacts
  5. Historical Populations of States and Counties (1790 - 1990)