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Butte County, Idaho facts for kids

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Butte County
Experimental Breeder Reactor I
Official seal of Butte County
Map of Idaho highlighting Butte County
Location within the U.S. state of Idaho
Map of the United States highlighting Idaho
Idaho's location within the U.S.
Country  United States
State  Idaho
Founded February 6, 1917
Named for Big Southern Butte
Seat Arco
Largest city Arco
 • Total 2,234 sq mi (5,790 km2)
 • Land 2,232 sq mi (5,780 km2)
 • Water 2.0 sq mi (5 km2)  0.1%
 • Total 2,574 Decrease
 • Density 1.3/sq mi (0.5/km2)
Time zone UTC−7 (Mountain)
 • Summer (DST) UTC−6 (MDT)
Congressional district 2nd

Butte County is a rural county located in the U.S. state of Idaho. As of the 2020 census, the population was 2,574, making it the third-least populous county in Idaho. Its county seat and largest city is Arco. The county was established in 1917 from parts of Bingham, Blaine, and Jefferson counties. The county gained territory in the Clyde area from Custer County in 1937 to reach its present boundary.


The first settlement in Butte County occurred about four miles south of the present town site of Arco in 1878. The settlement was then known by the names of Kennedy Crossing and Lower Crossing of the Lost River and was located in eastern Alturas County. Once the post office was established in 1879, the settlement became known as Arco.

The ghost town of Era was settled in 1885. Settlement of Antelope, Martin and Island (now Moore) also occurred prior to 1890. Alturas county established precincts for all five Butte County settlements existing at the 1890 census containing a combined population of 389. The settlements became part of Blaine County in 1895. Blaine County created precincts for all of the settlements except Martin and added a precinct for Clyde. At the 1900 census, the five precincts totaled 714 residents increasing to 1787 in 1910.Construction of a railroad from Blackfoot to Mackay resulted in relocation of the town of Arco to its present site in 1901.

Butte County is included in the Idaho Falls, ID Metropolitan Statistical Area. Much of the eastern part of the county is the vast Idaho National Laboratory, which extends eastward into neighboring counties.


Big Southern Butte at Craters of the Moon NM-750px
Big Southern Butte was used as a landmark by pioneers.

According to the U.S. Census Bureau, the county has a total area of 2,234 square miles (5,790 km2), of which 2,232 square miles (5,780 km2) is land and 2.0 square miles (5.2 km2) (0.1%) is water.

The Little Lost River is located in Butte County. Its waters, along with the Big Lost River, disappear from the surface to flow underground into the Snake River Plain aquifer in Butte County.

The county was named for the volcanic buttes that rise from the desert plain; the largest is Big Southern Butte, located in the southern part of the county. It rises 2,500 feet (760 m) above the desert floor and was used as a landmark by pioneers.

The southwestern portion of the county includes the visitor center at the Craters of the Moon National Monument and Preserve, which extends south & west into three other counties.

Adjacent counties


  • US 20.svg US 20
  • US 26.svg US 26
  • US 93.svg US 93
  • ID-22.svg SH-22
  • ID-33.svg SH-33

National protected areas


Historical population
Census Pop.
1920 2,940
1930 1,934 −34.2%
1940 1,877 −2.9%
1950 2,722 45.0%
1960 3,498 28.5%
1970 2,925 −16.4%
1980 3,342 14.3%
1990 2,918 −12.7%
2000 2,899 −0.7%
2010 2,891 −0.3%
2020 2,574 −11.0%
U.S. Decennial Census
1790-1960 1900-1990
1990-2000 2010-2020

2010 census

As of the 2010 United States Census, there were 2,891 people, 1,129 households, and 788 families living in the county. The population density was 1.3 inhabitants per square mile (0.50/km2). There were 1,354 housing units at an average density of 0.6 per square mile (0.23/km2). The racial makeup of the county was 95.5% white, 0.4% American Indian, 0.2% Pacific islander, 0.2% Asian, 0.2% black or African American, 2.0% from other races, and 1.5% from two or more races. Those of Hispanic or Latino origin made up 4.1% of the population. In terms of ancestry, 33.4% were English, 18.5% were German, 10.6% were American, 9.1% were Irish, 7.6% were Danish, and 7.2% were Scottish.

Of the 1,129 households, 31.5% had children under the age of 18 living with them, 58.8% were married couples living together, 7.8% had a female householder with no husband present, 30.2% were non-families, and 26.4% of all households were made up of individuals. The average household size was 2.54 and the average family size was 3.10. The median age was 41.7 years.

The median income for a household in the county was $39,413 and the median income for a family was $47,225. Males had a median income of $42,500 versus $26,563 for females. The per capita income for the county was $20,414. About 9.0% of families and 13.8% of the population were below the poverty line, including 17.2% of those under age 18 and 5.0% of those age 65 or over.


As of 2016 the largest self-reported ancestries/ethnicities in Butte County, Idaho were:

Largest ancestries (2016) Percent
English England 27.7%
"American" United States 17.4%
German Germany 11.8%
Irish Republic of Ireland 6.7%
Italian Italy 5.9%
Scottish Scotland 4.6%
French France 3.6%
Swedish Sweden 2.8%
Norwegian Norway 1.2%
Welsh Wales 1.3%



Unincorporated communities

  • Darlington
  • Lost River
  • Howe

See also

Kids robot.svg In Spanish: Condado de Butte (Idaho) para niños

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James B. Knighten
Azellia White
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