Ada County Flag

Ada County

State:
Idaho
County Seat:
Boise

Ada County's estimated 2025 population is 544,908 with a growth rate of 1.7% in the past year according to the most recent United States census data. Ada County is the largest county in Idaho. The 2010 population was 393,369 and has seen a growth of 38.52% since that time.

544,908
Total Population
518
Population Density (mi²)
1
Population Rank (State)
9.1K 1.7%
Annual Population Growth

Ada 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)