Sioux County Demographics

A map of Sioux County's Population by Race

Sioux County, Iowa has an estimated population of 36,212, a less than 1% change from the 35,872 recorded in the 2020 Census. The population is 82.8% White, 14.3% Hispanic, 1.3% Multiracial, 0.6% Black, 0.5% Asian, and 0.4% Native American/Other. This demographic dot map shows the population of Sioux County, with one dot drawn for each person counted by the Census, color-coded by race.

Sioux has become slightly more racially diverse since the 2020 Census. It is 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 Sioux County, that probability was 28.5% in 2020 and 29.4% in the most recent ACS estimates.

Sioux County is ranked the 19th most populous county in Iowa, out of 99 counties. Sioux County was ranked the 19th most populous county in the 2020 Census.

Sioux County's White Population

29,982 residents of Sioux County, or 82.8% of the population, identify as White. The share of White residents in Sioux County is comparable to the share in Iowa overall, where 82.3% of the population is White. Sioux County ranks 81st statewide in terms of White residents as a share of the population, out of 99 counties.

Since the 2020 Census, Sioux County's White population has remained roughly the same. White residents' share of Sioux County's population has decreased from 83.4% to 82.8%.

Sioux County is less White than neighboring Lyon County (93.4% White), Plymouth County (88% White), Union County (88.4% White), O'Brien County (87% White), and Lincoln County (89% White).

Sioux County's Black Population

214 residents of Sioux County, or 0.6% of the population, identify as Black. The share of Black residents in Sioux County is slightly lower than in Iowa overall, where 3.8% of the population is Black. Sioux County ranks 65th statewide in terms of Black residents as a share of the population, out of 99 counties.

Since the 2020 Census, Sioux County's Black population has grown by an estimated 16.3%. Black residents' share of Sioux County's population has remained roughly unchanged at 0.6%.

Sioux County is more Black than neighboring Lyon County (0.4% Black). Sioux County is less Black than neighboring Plymouth County (2.4% Black), Union County (0.9% Black), O'Brien County (1.7% Black), and Lincoln County (2.3% Black).

Sioux County's Asian Population

197 residents of Sioux County, or 0.5% of the population, identify as Asian. The share of Asian residents in Sioux County is comparable to the share in Iowa overall, where 2.5% of the population is Asian. Sioux County ranks 34th statewide in terms of Asian residents as a share of the population, out of 99 counties.

Since the 2020 Census, Sioux County's Asian population has declined by an estimated 10.0%. Asian residents' share of Sioux County's population has remained roughly unchanged at 0.5%.

Sioux County is less Asian than neighboring Union County (1.1% Asian), O'Brien County (0.7% Asian), and Lincoln County (1.7% Asian).

Sioux County's Hispanic Population

5,193 residents of Sioux County, or 14.3% of the population, identify as Hispanic. The share of Hispanic residents in Sioux County is higher than in Iowa overall, where 7.3% of the population is Hispanic. Sioux County ranks 10th statewide in terms of Hispanic residents as a share of the population, out of 99 counties.

Since the 2020 Census, Sioux County's Hispanic population has grown by an estimated 5.7%. Hispanic residents' share of Sioux County's population has increased from 13.7% to 14.3%.

Sioux County is more Hispanic than neighboring Lyon County (3.9% Hispanic), Plymouth County (6.4% Hispanic), Union County (4.8% Hispanic), O'Brien County (7.6% Hispanic), and Lincoln County (3.2% Hispanic).

Sioux County's Native American/Other Population

160 residents of Sioux County, or 0.4% of the population, identify as American Indian/Alaska Native/Native Hawaiian/Pacific Islander/Other. The share of Native American/Other residents in Sioux County is comparable to the share in Iowa overall, where 0.6% of the population is Native American/Other. Sioux County ranks 61st statewide in terms of Native American/Other residents as a share of the population, out of 99 counties.

Since the 2020 Census, Sioux County's Native American/Other population has grown by an estimated 19.4%. Native American/Other residents' share of Sioux County's population has remained roughly unchanged at 0.4%.

Sioux County is more Native American/Other than neighboring Lyon County (0.1% Native American/Other). Sioux County is less Native American/Other than neighboring Plymouth County (0.7% Native American/Other), Union County (1% Native American/Other), O'Brien County (0.5% Native American/Other), and Lincoln County (0.8% Native American/Other).

Sioux County's Multiracial Population

466 residents of Sioux County, or 1.3% of the population, identify as Multiracial. The share of Multiracial residents in Sioux County is slightly lower than in Iowa overall, where 3.5% of the population is Multiracial. Sioux County ranks 99th statewide in terms of Multiracial residents as a share of the population, out of 99 counties.

Since the 2020 Census, Sioux County's Multiracial population has declined by an estimated 7.2%. Multiracial residents' share of Sioux County's population has remained roughly unchanged at 1.3%.

Sioux County is less Multiracial than neighboring Lyon County (1.8% Multiracial), Plymouth County (2% Multiracial), Union County (3.7% Multiracial), O'Brien County (2.6% Multiracial), and Lincoln County (3% 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.