Yellowstone County, Montana
Yellowstone County is the most populous county in the U.S. state of Montana. As of the 2020 census, the population was 164,731.  Its county seat is Billings, the state's most populous city. Like the nearby 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 included in the Billings, Montana Metropolitan Statistical Area.

Geography
According to the United States Census Bureau, the county has a total area of , of which  is land and  (0.6%) is water.

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

2020 census
As of the census of 2020 there were 164,731 people.

2010 census
As of the census of 2010, 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 90.7% white, 4.0% American Indian, 0.6% black or African American, 0.6% Asian, 0.1% Pacific islander, 1.2% from other races, and 2.8% from two or more races. Those of Hispanic or Latino origin made up 4.7% 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 rather conservative for an urban county. Its voters have been reliably Republican for the better part of a century. They have selected the Democratic Party candidate in only one national election since 1940 (as of 2020).

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

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
County website

 
Billings metropolitan area
1883 establishments in Montana Territory
Populated places established in 1883