Washington County Demographics

A map of Washington County's Population by Race

Race	2024 Pop	2020 Pop	2024 %	2020 %
White	20,008	19,958	88.7%	88.4%
Hispanic	1,749	1,612	7.8%	7.1%
Multiracial	447	601	2.0%	2.7%
Black	236	177	1.0%	0.8%
Asian	87	113	0.4%	0.5%
Native American/Other	34	104	0.2%	0.5%

Washington County, Iowa has an estimated population of 22,561, a less than 1% change from the 22,565 recorded in the 2020 Census. The population is 88.7% White, 7.8% Hispanic, 2.0% Multiracial, 1.0% Black, 0.4% Asian, and 0.2% Native American/Other. This demographic dot map shows the population of Washington County, with one dot drawn for each person counted by the Census, color-coded by race.

Washington is about as racially diverse as it was in the 2020 Census. It is considerably less diverse than Iowa overall. Demographers use a diversity index to measure the probability that two randomly selected individuals belong to different racial or ethnic groups. In Washington County, that probability was 21.2% in 2020 and 20.7% in the most recent ACS estimates.

Washington County is ranked the 27th most populous county in Iowa, out of 99 counties. Washington County was ranked the 27th most populous county in the 2020 Census.

Washington County's White Population

20,008 residents of Washington County, or 88.7% of the population, identify as White. The share of White residents in Washington County is higher than in Iowa overall, where 82.3% of the population is White. Washington County ranks 69th statewide in terms of White residents as a share of the population, out of 99 counties.

Since the 2020 Census, Washington County's White population has remained roughly the same. White residents' share of Washington County's population has remained roughly unchanged at 88.7%.

Washington County is more White than neighboring Johnson County (74.8% White), Jefferson County (82.4% White), Henry County (86.2% White), and Louisa County (77% White). Washington County is less White than neighboring Keokuk County (94.6% White).

Washington County's Black Population

236 residents of Washington County, or 1.0% of the population, identify as Black. The share of Black residents in Washington County is slightly lower than in Iowa overall, where 3.8% of the population is Black. Washington County ranks 47th statewide in terms of Black residents as a share of the population, out of 99 counties.

Since the 2020 Census, Washington County's Black population has grown by an estimated 33.3%. Black residents' share of Washington County's population has remained roughly unchanged at 1.0%.

Washington County is more Black than neighboring Keokuk County (0.3% Black), and Louisa County (0.9% Black). Washington County is less Black than neighboring Johnson County (7.6% Black), Jefferson County (2.4% Black), and Henry County (2.5% Black).

Washington County's Asian Population

87 residents of Washington County, or 0.4% of the population, identify as Asian. The share of Asian residents in Washington County is slightly lower than in Iowa overall, where 2.5% of the population is Asian. Washington County ranks 46th statewide in terms of Asian residents as a share of the population, out of 99 counties.

Since the 2020 Census, Washington County's Asian population has declined by an estimated 23.0%. Asian residents' share of Washington County's population has remained roughly unchanged at 0.4%.

Washington County is more Asian than neighboring Keokuk County (0.2% Asian). Washington County is less Asian than neighboring Johnson County (5.6% Asian), Jefferson County (8.2% Asian), Henry County (0.9% Asian), and Louisa County (2.2% Asian).

Washington County's Hispanic Population

1,749 residents of Washington County, or 7.8% of the population, identify as Hispanic. The share of Hispanic residents in Washington County is comparable to the share in Iowa overall, where 7.3% of the population is Hispanic. Washington County ranks 19th statewide in terms of Hispanic residents as a share of the population, out of 99 counties.

Since the 2020 Census, Washington County's Hispanic population has grown by an estimated 8.5%. Hispanic residents' share of Washington County's population has increased from 7.1% to 7.8%.

Washington County is more Hispanic than neighboring Johnson County (6.7% Hispanic), Jefferson County (4.1% Hispanic), Henry County (5.5% Hispanic), and Keokuk County (2.3% Hispanic). Washington County is less Hispanic than neighboring Louisa County (16.4% Hispanic).

Washington County's Native American/Other Population

34 residents of Washington County, or 0.2% of the population, identify as American Indian/Alaska Native/Native Hawaiian/Pacific Islander/Other. The share of Native American/Other residents in Washington County is comparable to the share in Iowa overall, where 0.6% of the population is Native American/Other. Washington County ranks 51st statewide in terms of Native American/Other residents as a share of the population, out of 99 counties.

Since the 2020 Census, Washington County's Native American/Other population has declined by an estimated 67.3%. Native American/Other residents' share of Washington County's population has remained roughly unchanged at 0.2%.

Washington County is more Native American/Other than neighboring Louisa County (0.1% Native American/Other). Washington County is less Native American/Other than neighboring Johnson County (0.6% Native American/Other), Jefferson County (0.4% Native American/Other), Henry County (0.4% Native American/Other), and Keokuk County (0.3% Native American/Other).

Washington County's Multiracial Population

447 residents of Washington County, or 2.0% of the population, identify as Multiracial. The share of Multiracial residents in Washington County is comparable to the share in Iowa overall, where 3.5% of the population is Multiracial. Washington County ranks 41st statewide in terms of Multiracial residents as a share of the population, out of 99 counties.

Since the 2020 Census, Washington County's Multiracial population has declined by an estimated 25.6%. Multiracial residents' share of Washington County's population has decreased from 2.7% to 2.0%.

Washington County is less Multiracial than neighboring Johnson County (4.6% Multiracial), Jefferson County (2.5% Multiracial), Henry County (4.4% Multiracial), Keokuk County (2.3% Multiracial), and Louisa County (3.4% 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.