Yellowstone County

administration
[[File: Yellowstone County Courthouse with US Post Office, listed on NRHP \| 298px \| Madison County Courthouse]] Madison County Courthouse
US state :	Montana
Administrative headquarters :	Billings
Foundation :	1893
Demographics
Residents :	147,972 (2010)
Population density :	21.7 inhabitants / km ²
geography
Total area :	6861 km²
Water surface :	36 km²
map

Yellowstone County is a county in the state of Montana in the United States . The county seat is in Billings .

Demographic data

growth of population
Census	Residents	± in%
1890	2065	-
1900	6212	200.8%
1910	22,944	269.3%
1920	29,600	29%
1930	30,785	4%
1940	41,182	33.8%
1950	55,875	35.7%
1960	79,016	41.4%
1970	87,367	10.6%
1980	108.035	23.7%
1990	113.419	5%
2000	129,352	14%
2010	147.972	14.4%
Before 1900, 1900–1990, 2000 + 2010

According to the 2000 census , the county had 129,352 people. There were 52,084 households and 34,219 families. The population density was 19 inhabitants per square kilometer. The racial the population was composed of 92.78% White, 0.45% African American, 3.05% Native American, 0.54% Asian, 0.04% Pacific Islander, and 1.26% other races Groups; 1.87% were from two or more races. 3.70% of the population were Hispanic or Latino of any race.

Of the 52,084 households, 31.60% had children and adolescents under the age of 18 living with them. 51.80% were married couples living together, 10.10% were single mothers. 34.30% were not families. 27.90% were single households and 10.10% had someone who was 65 years of age or older. The average household size was 2.43 and the average family size was 2.98 people.

Yellowstone County's age pyramid (as of 2000)

The Yellowstone River near Huntley

For the entire county, the population was composed of 25.50% residents under 18 years of age, 9.30% between 18 and 24 years of age, 28.70% between 25 and 44 years of age, and 23.20% between 45 and 64 years of age 13.30% were 65 years of age or over. The median age was 37 years. For every 100 females there were 95.20 males, for every 100 females aged 18 and over there were 91.60 males.

The median income for a household in the county is $ 36,727 , and the median income for a family is $ 45,277. Males had a median income of $ 33,475 versus $ 21,566 for females. The per capita income was $ 19,303. 11.10% of the population and 8.50% of families are below the poverty line. 14.50% of these were under 18 years of age and 7.40% were 65 years of age or older.