Ada County Demographics

A map of Ada County's Population by Race

Ada County, Idaho has an estimated population of 518,935, an increase from the 494,967 recorded in the 2020 Census. The population is 80.9% White, 9.8% Hispanic, 4.3% Multiracial, 2.7% Asian, 1.3% Black, and 1.0% Native American/Other. This demographic dot map shows the population of Ada County, with one dot drawn for each person counted by the Census, color-coded by race.

Ada has become slightly less racially diverse since the 2020 Census. It is less diverse than Idaho overall. Demographers use a diversity index to measure the probability that two randomly selected individuals belong to different racial or ethnic groups. In Ada County, that probability was 34.2% in 2020 and 33.3% in the most recent ACS estimates.

Ada County is ranked the most populous county in Idaho, out of 44 counties. Ada County was ranked the 1st most populous county in the 2020 Census.

Ada County's White Population

419,728 residents of Ada County, or 80.9% of the population, identify as White. The share of White residents in Ada County is slightly higher than in Idaho overall, where 78.6% of the population is White. Ada County ranks 28th statewide in terms of White residents as a share of the population, out of 44 counties.

Since the 2020 Census, Ada County's White population has grown by an estimated 5.5%. White residents' share of Ada County's population has increased from 80.4% to 80.9%.

Ada County is more White than neighboring Canyon County (67.1% White), Payette County (75.5% White), and Elmore County (69.5% White). Ada County is less White than neighboring Gem County (83.5% White), and Boise County (83.5% White).

Ada County's Black Population

6,536 residents of Ada County, or 1.3% of the population, identify as Black. The share of Black residents in Ada County is comparable to the share in Idaho overall, where 0.7% of the population is Black. Ada County ranks 2nd statewide in terms of Black residents as a share of the population, out of 44 counties.

Since the 2020 Census, Ada County's Black population has declined by an estimated 15.5%. Black residents' share of Ada County's population has remained roughly unchanged at 1.3%.

Ada County is more Black than neighboring Canyon County (0.7% Black), Gem County (0% Black), Boise County (0.2% Black), and Payette County (0.1% Black). Ada County is less Black than neighboring Elmore County (2.8% Black).

Ada County's Asian Population

14,215 residents of Ada County, or 2.7% of the population, identify as Asian. The share of Asian residents in Ada County is comparable to the share in Idaho overall, where 1.3% of the population is Asian. Ada County ranks 1st statewide in terms of Asian residents as a share of the population, out of 44 counties.

Since the 2020 Census, Ada County's Asian population has grown by an estimated 4.1%. Asian residents' share of Ada County's population has remained roughly unchanged at 2.7%.

Ada County is more Asian than neighboring Canyon County (0.8% Asian), Gem County (0.8% Asian), Boise County (1.5% Asian), Payette County (0.7% Asian), and Elmore County (2.6% Asian).

Ada County's Hispanic Population

50,948 residents of Ada County, or 9.8% of the population, identify as Hispanic. The share of Hispanic residents in Ada County is slightly lower than in Idaho overall, where 13.6% of the population is Hispanic. Ada County ranks 22nd statewide in terms of Hispanic residents as a share of the population, out of 44 counties.

Since the 2020 Census, Ada County's Hispanic population has grown by an estimated 12.7%. Hispanic residents' share of Ada County's population has increased from 9.1% to 9.8%.

Ada County is more Hispanic than neighboring Gem County (9.7% Hispanic), and Boise County (5.1% Hispanic). Ada County is less Hispanic than neighboring Canyon County (26% Hispanic), Payette County (17.9% Hispanic), and Elmore County (18.2% Hispanic).

Ada County's Native American/Other Population

5,002 residents of Ada County, or 1.0% of the population, identify as American Indian/Alaska Native/Native Hawaiian/Pacific Islander/Other. The share of Native American/Other residents in Ada County is comparable to the share in Idaho overall, where 1.5% of the population is Native American/Other. Ada County ranks 22nd statewide in terms of Native American/Other residents as a share of the population, out of 44 counties.

Since the 2020 Census, Ada County's Native American/Other population has declined by an estimated 16.3%. Native American/Other residents' share of Ada County's population has remained roughly unchanged at 1.0%.

Ada County is less Native American/Other than neighboring Canyon County (1.4% Native American/Other), Gem County (1.5% Native American/Other), Boise County (3.2% Native American/Other), Payette County (1.6% Native American/Other), and Elmore County (1.6% Native American/Other).

Ada County's Multiracial Population

22,506 residents of Ada County, or 4.3% of the population, identify as Multiracial. The share of Multiracial residents in Ada County is comparable to the share in Idaho overall, where 4.2% of the population is Multiracial. Ada County ranks 7th statewide in terms of Multiracial residents as a share of the population, out of 44 counties.

Since the 2020 Census, Ada County's Multiracial population has declined by an estimated 7.7%. Multiracial residents' share of Ada County's population has decreased from 4.9% to 4.3%.

Ada County is more Multiracial than neighboring Canyon County (4% Multiracial), and Payette County (4.2% Multiracial). Ada County is less Multiracial than neighboring Gem County (4.5% Multiracial), Boise County (6.5% Multiracial), and Elmore County (5.2% Multiracial).

Sources: Most recent population estimates are from the 2020-2024 American Community Survey 5-Year Estimates. 2020 population counts and map data are from 2020 Census State Redistricting Data. Geographic data are from Census TIGER/Line Shapefiles.