Dewey County Demographics

A map of Dewey County's Population by Race

Race	2024 Pop	2020 Pop	2024 %	2020 %
Native American/Other	3,841	4,086	73.8%	78.0%
White	1,094	849	21.0%	16.2%
Multiracial	186	208	3.6%	4.0%
Hispanic	54	81	1.0%	1.5%
Black	27	9	0.5%	0.2%
Asian	3	6	0.1%	0.1%

Dewey County, South Dakota has an estimated population of 5,205, a less than 1% change from the 5,239 recorded in the 2020 Census. The population is 73.8% Native American/Other, 21.0% White, 3.6% Multiracial, 1.0% Hispanic, 0.5% Black, and 0.1% Asian. This demographic dot map shows the population of Dewey County, with one dot drawn for each person counted by the Census, color-coded by race.

Dewey has become more racially diverse since the 2020 Census. It is considerably more diverse than South Dakota overall. Demographers use a diversity index to measure the probability that two randomly selected individuals belong to different racial or ethnic groups. In Dewey County, that probability was 36.4% in 2020 and 41.0% in the most recent ACS estimates.

Dewey County is ranked the 36th most populous county in South Dakota, out of 66 counties. Dewey County was ranked the 35th most populous county in the 2020 Census.

Dewey County's White Population

1,094 residents of Dewey County, or 21.0% of the population, identify as White. The share of White residents in Dewey County is significantly lower than in South Dakota overall, where 79.8% of the population is White. Dewey County ranks 63rd statewide in terms of White residents as a share of the population, out of 66 counties.

Since the 2020 Census, Dewey County's White population has grown by an estimated 28.9%. White residents' share of Dewey County's population has increased from 16.2% to 21.0%.

Dewey County is less White than neighboring Corson County (29.9% White), Stanley County (87.9% White), Ziebach County (27.1% White), Sully County (86.5% White), and Walworth County (78.2% White).

Dewey County's Black Population

27 residents of Dewey County, or 0.5% of the population, identify as Black. The share of Black residents in Dewey County is comparable to the share in South Dakota overall, where 2.1% of the population is Black. Dewey County ranks 42nd statewide in terms of Black residents as a share of the population, out of 66 counties.

Since the 2020 Census, Dewey County's Black population has grown by an estimated 200.0%. Black residents' share of Dewey County's population has remained roughly unchanged at 0.5%.

Dewey County is more Black than neighboring Corson County (0% Black), Stanley County (0% Black), Ziebach County (0% Black), and Walworth County (0.3% Black). Dewey County is less Black than neighboring Sully County (4.5% Black).

Dewey County's Asian Population

3 residents of Dewey County, or 0.1% of the population, identify as Asian. The share of Asian residents in Dewey County is comparable to the share in South Dakota overall, where 1.4% of the population is Asian. Dewey County ranks 55th statewide in terms of Asian residents as a share of the population, out of 66 counties.

Since the 2020 Census, Dewey County's Asian population has declined by an estimated 50.0%. Asian residents' share of Dewey County's population has remained roughly unchanged at 0.1%.

Dewey County is more Asian than neighboring Corson County (0% Asian), Stanley County (0% Asian), Ziebach County (0% Asian), and Sully County (0% Asian). Dewey County is less Asian than neighboring Walworth County (0.6% Asian).

Dewey County's Hispanic Population

54 residents of Dewey County, or 1.0% of the population, identify as Hispanic. The share of Hispanic residents in Dewey County is slightly lower than in South Dakota overall, where 4.8% of the population is Hispanic. Dewey County ranks 54th statewide in terms of Hispanic residents as a share of the population, out of 66 counties.

Since the 2020 Census, Dewey County's Hispanic population has declined by an estimated 33.3%. Hispanic residents' share of Dewey County's population has decreased from 1.5% to 1.0%.

Dewey County is more Hispanic than neighboring Corson County (0.5% Hispanic), Sully County (0% Hispanic), and Walworth County (0.6% Hispanic). Dewey County is less Hispanic than neighboring Stanley County (2.2% Hispanic), and Ziebach County (1.5% Hispanic).

Dewey County's Native American/Other Population

3,841 residents of Dewey County, or 73.8% of the population, identify as American Indian/Alaska Native/Native Hawaiian/Pacific Islander/Other. The share of Native American/Other residents in Dewey County is significantly higher than in South Dakota overall, where 7.5% of the population is Native American/Other. Dewey County ranks 5th statewide in terms of Native American/Other residents as a share of the population, out of 66 counties.

Since the 2020 Census, Dewey County's Native American/Other population has declined by an estimated 6.0%. Native American/Other residents' share of Dewey County's population has decreased from 78.0% to 73.8%.

Dewey County is more Native American/Other than neighboring Corson County (66.5% Native American/Other), Stanley County (3.5% Native American/Other), Ziebach County (69.5% Native American/Other), Sully County (4.3% Native American/Other), and Walworth County (10.9% Native American/Other).

Dewey County's Multiracial Population

186 residents of Dewey County, or 3.6% of the population, identify as Multiracial. The share of Multiracial residents in Dewey County is comparable to the share in South Dakota overall, where 4.4% of the population is Multiracial. Dewey County ranks 21st statewide in terms of Multiracial residents as a share of the population, out of 66 counties.

Since the 2020 Census, Dewey County's Multiracial population has declined by an estimated 10.6%. Multiracial residents' share of Dewey County's population has remained roughly unchanged at 3.6%.

Dewey County is more Multiracial than neighboring Corson County (3% Multiracial), and Ziebach County (1.9% Multiracial). Dewey County is less Multiracial than neighboring Stanley County (6.4% Multiracial), Sully County (4.7% Multiracial), and Walworth County (9.5% 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.