New Castle County Flag

New Castle County

State:
Delaware
County Seat:
Wilmington

New Castle County's estimated 2025 population is 593,861 with a growth rate of 0.98% in the past year according to the most recent United States census data. New Castle County is the largest county in Delaware. The 2010 population was 538,792 and has seen a growth of 10.22% since that time.

593,861
Total Population
1,394
Population Density (mi²)
1
Population Rank (State)
5.8K 0.98%
Annual Population Growth

New Castle County Population

Demographics

Economics and Income Statistics

Sources

  1. City and Town Population Totals: 2020-2024
  2. US Census State Population Estimates - Most recent state estimates from the Census Bureau's Population Estimates Program
  3. US Census County Population Estimates - Most recent county estimates from the Census Bureau's Population Estimates Program
  4. American Community Survey (2009 - 2013)
  5. Census QuickFacts
  6. Historical Populations of States and Counties (1790 - 1990)