Yellowstone County is a county in the U.S. state of Montana. As of the 2020 census, the population was 164,731, and was estimated to be 172,692 in 2025, making it the most populous county in Montana. The county seat and the largest city is Billings, the most populous city in Montana and the 253rd-most populous city in the United States. It contains over 15.09% of the state's population.Based on the 2025 Estimate: 172,692 / 1,144,694 (MT pop.) = 15.09% Like the nearby national park, Yellowstone County is named after the Yellowstone River which roughly bisects the county, flowing southwest to northeast. The river, in turn, was named for the yellow sandstone cliffs in what is now Yellowstone County.

Yellowstone County is part of the Billings metropolitan area, which comprises all of Carbon, Stillwater, and Yellowstone Counties.

History Yellowstone County was created on February 26, 1883 and organized on May 1, 1883.

Geography According to the United States Census Bureau, the county has a total area of , of which is land and (0.59%) is water. It is the 23rd largest county in Montana by total area.

Major highways

Transit Billings Metropolitan Transit Express Arrow Jefferson Lines

Adjacent counties

Musselshell County – north Rosebud County – northeast Treasure County – east Big Horn County – southeast Carbon County – southwest Stillwater County – west Golden Valley County – northwest

National protected areas Nez Perce National Historical Park (part) Pompeys Pillar National Monument

Demographics

As of the fourth quarter of 2025, the median home value in Yellowstone County was $386,158.

As of the 2024 American Community Survey, there are 70,714 estimated households in Yellowstone County with an average of 2.37 persons per household. The county has a median household income of $76,858. Approximately 7.9% of the county's population lives at or below the poverty line. Yellowstone County has an estimated 63.7% employment rate, with 32.2% of the population holding a bachelor's degree or higher and 93.8% holding a high school diploma. There were 75,777 housing units at an average density of .

The median age in the county was 40.2 years.

+Yellowstone County, Montana – racial and ethnic composition Race / ethnicity (NH = non-Hispanic) Pop. 1980 Pop. 1990 Pop. 2000 Pop. 2010 Pop. 2024 White alone (NH) 102,178(94.58%) 106,068(93.52%) 117,698(90.99%) 130,463(88.17%) 136,514(82.87%) 144,651(84.30%) Black or African American alone (NH) 2690.25%) 4650.41%) 5420.42%) 852(0.58%) 1,187(0.72%) 1,031(0.60%) Native American or Alaska Native alone (NH) 2,2682.10%) 3,0862.72%) 3,6762.84%) 5,377(3.63%) 6,546(3.97%) 7,255(4.23%) Asian alone (NH) 372(0.34%) 604(0.53%) 666(0.51%) 915(0.62%) 1,279(0.78%) 1,290(0.75%) Pacific Islander alone (NH) — — 54(0.04%) 104(0.07%) 211(0.13%) 135(0.08%) Other race alone (NH) 57(0.05%) 38(0.03%) 66(0.05%) 84(0.06%) 576(0.35%) — Mixed race or multiracial (NH) — — 1,862(1.44%) 3,222(2.18%) 8,303(5.04%) 5,130(2.99%) Hispanic or Latino (any race) 2,891(2.68%) 3,158(2.78%) 4,788(3.70%) 6,955(4.70%) 10,115(6.14%) 12,091(7.05%) Total 108,035(100.00%) 113,419(100.00%) 129,352(100.00%) 147,972(100.00%) 164,731(100.00%) 171,583(100.00%)

2024 estimate As of the 2024 estimate, there were 171,583 people, 70,714 households, and _ families residing in the county. The population density was . There were 75,777 housing units at an average density of . The racial makeup of the county was 89.60% White, 0.68% African American, 5.36% Native American, 0.82% Asian, 0.10% Pacific Islander, _% from some other races and 3.44% from two or more races. Hispanic or Latino people of any race were 7.05% of the population.

2020 census As of the 2020 census, there were 164,731 people, 67,578 households, and 42,022 families residing in the county. The population density was . There were 71,804 housing units at an average density of . The racial makeup of the county was 84.97% White, 0.79% African American, 4.39% Native American, 0.80% Asian, 0.14% Pacific Islander, 1.72% from some other races and 7.19% from two or more races. Hispanic or Latino people of any race were 6.14% of the population.

There were 67,578 households in the county, of which 28.6% had children under the age of 18 living with them and 26.7% had a female householder with no spouse or partner present. About 30.5% of all households were made up of individuals and 12.4% had someone living alone who was 65 years of age or older.

Of the residents, 23.2% were under the age of 18 and 17.8% were 65 years of age or older; the median age was 38.8 years. For every 100 females there were 96.4 males, and for every 100 females age 18 and over there were 93.9 males. Among occupied housing units, 66.3% were owner-occupied and 33.7% were renter-occupied. The homeowner vacancy rate was 1.4% and the rental vacancy rate was 7.1%.

2010 census As of the 2010 census, there were 147,972 people, 60,672 households, and 38,367 families residing in the county. The population density was . There were 63,943 housing units at an average density of . The racial makeup of the county was 90.71% White, 0.63% African American, 3.97% Native American, 0.63% Asian, 0.08% Pacific Islander, 1.19% from some other races and 2.78% from two or more races. Hispanic or Latino people of any race were 4.70% of the population.

In terms of ancestry, 32.4% were German, 14.0% were Irish, 11.3% were English, 10.0% were American, and 9.9% were Norwegian.

Of the 60,672 households, 30.5% had children under the age of 18 living with them, 48.0% were married couples living together, 10.5% had a female householder with no husband present, 36.8% were non-families, and 29.7% of all households were made up of individuals. The average household size was 2.38 and the average family size was 2.94. The median age was 38.3 years.

The median income for a household in the county was $48,641 and the median income for a family was $62,380. Males had a median income of $42,899 versus $30,403 for females. The per capita income for the county was $26,152. About 7.9% of families and 11.2% of the population were below the poverty line, including 15.6% of those under age 18 and 7.7% of those age 65 or over.

Politics Yellowstone County is very conservative for an urban county. Its voters have been reliably Republican for the better part of a century. Lyndon B. Johnson's 1964 landslide was the last time that the county voted for a Democratic candidate.

Communities Cities Billings (county seat) Laurel

Town Broadview

Census-designated places

Acton Ballantine Custer Huntley Lockwood Mountain View Colony Nibbe Pompeys Pillar Shepherd Worden

Other unincorporated communities

Anita Billings Heights Bull Mountain Comanche Hesper Homewood Park Indian Arrow Newton Osborn Yegen

Ghost towns

Coulson Mossmain Rimrock Waco

Education School districts include: - Text list

K-12 (unified): Custer K-12 Schools Huntley Project K-12 Schools Lockwood K-12 Schools

High school districts: Billings High School District Broadview High School District Laurel High School District Shepherd High School District

Elementary school districts: Billings Elementary School District Blue Creek Elementary School District Broadview Elementary School District Canyon Creek Elementary School District Elder Grove Elementary School District Elysian Elementary School District Independent Elementary School District Laurel Elementary School District Molt Elementary School District Morin Elementary School District Pioneer Elementary School District Shepherd Elementary School District Yellowstone Academy Elementary School District

See also List of lakes in Yellowstone County, Montana List of mountains in Yellowstone County, Montana National Register of Historic Places listings in Yellowstone County, Montana

References

External links Yellowstone County – official website