Stillwater County Demographics

A map of Stillwater County's Population by Race

Race	2024 Pop	2020 Pop	2024 %	2020 %
White	8,446	8,110	92.0%	90.5%
Multiracial	340	431	3.7%	4.8%
Hispanic	319	269	3.5%	3.0%
Native American/Other	39	118	0.4%	1.3%
Asian	34	22	0.4%	0.2%
Black	4	13	0.0%	0.1%

Stillwater County, Montana has an estimated population of 9,182, a slight increase from the 8,963 recorded in the 2020 Census. The population is 92.0% White, 3.7% Multiracial, 3.5% Hispanic, 0.4% Asian, 0.4% Native American/Other, and 0.0% Black. This demographic dot map shows the population of Stillwater County, with one dot drawn for each person counted by the Census, color-coded by race.

Stillwater has become less racially diverse since the 2020 Census. It is considerably less diverse than Montana overall. Demographers use a diversity index to measure the probability that two randomly selected individuals belong to different racial or ethnic groups. In Stillwater County, that probability was 17.8% in 2020 and 15.1% in the most recent ACS estimates.

Stillwater County is ranked the 25th most populous county in Montana, out of 56 counties. Stillwater County was ranked the 24th most populous county in the 2020 Census.

Stillwater County's White Population

8,446 residents of Stillwater County, or 92.0% of the population, identify as White. The share of White residents in Stillwater County is higher than in Montana overall, where 83.6% of the population is White. Stillwater County ranks 18th statewide in terms of White residents as a share of the population, out of 56 counties.

Since the 2020 Census, Stillwater County's White population has grown by an estimated 4.1%. White residents' share of Stillwater County's population has increased from 90.5% to 92.0%.

Stillwater County is more White than neighboring Sweet Grass County (90.8% White), Carbon County (90.1% White), Golden Valley County (90.3% White), and Park County (90.9% White). Stillwater County is less White than neighboring Wheatland County (94.2% White).

Stillwater County's Black Population

4 residents of Stillwater County, or 0.0% of the population, identify as Black. The share of Black residents in Stillwater County is comparable to the share in Montana overall, where 0.4% of the population is Black. Stillwater County ranks 38th statewide in terms of Black residents as a share of the population, out of 56 counties.

Since the 2020 Census, Stillwater County's Black population has declined by an estimated 69.2%. Black residents' share of Stillwater County's population has remained roughly unchanged at 0.0%.

Stillwater County is less Black than neighboring Sweet Grass County (1% Black), Carbon County (0.3% Black), Golden Valley County (0.8% Black), Wheatland County (1% Black), and Park County (0.2% Black).

Stillwater County's Asian Population

34 residents of Stillwater County, or 0.4% of the population, identify as Asian. The share of Asian residents in Stillwater County is comparable to the share in Montana overall, where 0.8% of the population is Asian. Stillwater County ranks 41st statewide in terms of Asian residents as a share of the population, out of 56 counties.

Since the 2020 Census, Stillwater County's Asian population has grown by an estimated 54.5%. Asian residents' share of Stillwater County's population has remained roughly unchanged at 0.4%.

Stillwater County is more Asian than neighboring Sweet Grass County (0.2% Asian), Carbon County (0% Asian), Golden Valley County (0% Asian), Wheatland County (0.3% Asian), and Park County (0.2% Asian).

Stillwater County's Hispanic Population

319 residents of Stillwater County, or 3.5% of the population, identify as Hispanic. The share of Hispanic residents in Stillwater County is comparable to the share in Montana overall, where 4.6% of the population is Hispanic. Stillwater County ranks 24th statewide in terms of Hispanic residents as a share of the population, out of 56 counties.

Since the 2020 Census, Stillwater County's Hispanic population has grown by an estimated 18.6%. Hispanic residents' share of Stillwater County's population has increased from 3.0% to 3.5%.

Stillwater County is more Hispanic than neighboring Sweet Grass County (1.2% Hispanic), Carbon County (3% Hispanic), and Wheatland County (2.5% Hispanic). Stillwater County is less Hispanic than neighboring Golden Valley County (4.3% Hispanic), and Park County (3.6% Hispanic).

Stillwater County's Native American/Other Population

39 residents of Stillwater 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 Stillwater County is lower than in Montana overall, where 5.9% of the population is Native American/Other. Stillwater County ranks 40th statewide in terms of Native American/Other residents as a share of the population, out of 56 counties.

Since the 2020 Census, Stillwater County's Native American/Other population has declined by an estimated 66.9%. Native American/Other residents' share of Stillwater County's population has decreased from 1.3% to 0.4%.

Stillwater County is less Native American/Other than neighboring Sweet Grass County (2.4% Native American/Other), Carbon County (2% Native American/Other), Golden Valley County (0.8% Native American/Other), Wheatland County (0.6% Native American/Other), and Park County (0.6% Native American/Other).

Stillwater County's Multiracial Population

340 residents of Stillwater County, or 3.7% of the population, identify as Multiracial. The share of Multiracial residents in Stillwater County is comparable to the share in Montana overall, where 4.7% of the population is Multiracial. Stillwater County ranks 25th statewide in terms of Multiracial residents as a share of the population, out of 56 counties.

Since the 2020 Census, Stillwater County's Multiracial population has declined by an estimated 21.1%. Multiracial residents' share of Stillwater County's population has decreased from 4.8% to 3.7%.

Stillwater County is more Multiracial than neighboring Wheatland County (1.5% Multiracial). Stillwater County is less Multiracial than neighboring Sweet Grass County (4.4% Multiracial), Carbon County (4.5% Multiracial), Golden Valley County (3.8% Multiracial), and Park County (4.5% 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.