Arco is a city in Butte County

Butte County, Idaho

Butte County is a rural county located in the U.S. state of Idaho. It was established in 1917, and its county seat and largest city is Arco. As of the 2010 census, the county had a population of 2,891...

, Idaho

Idaho

Idaho is a state in the Rocky Mountain area of the United States. The state's largest city and capital is Boise. Residents are called "Idahoans". Idaho was admitted to the Union on July 3, 1890, as the 43rd state....

, United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

. The population was 995 at the 2010 census. The city is the county seat

County seat

A county seat is an administrative center, or seat of government, for a county or civil parish. The term is primarily used in the United States....

 of Butte County

Butte County, Idaho

Butte County is a rural county located in the U.S. state of Idaho. It was established in 1917, and its county seat and largest city is Arco. As of the 2010 census, the county had a population of 2,891...

.

Craters of the Moon National Monument

Craters of the Moon National Monument and Preserve

Craters of the Moon National Monument and Preserve is a national monument and national preserve located in the Snake River Plain in central Idaho, U.S.A. It is along US 20 , between the small cities of Arco and Carey, at an average elevation of above sea level...

 is located along U.S. Route 20

U.S. Route 20

U.S. Route 20 is an east–west United States highway. As the "0" in its route number implies, US 20 is a coast-to-coast route. Spanning , it is the longest road in the United States, and the route sparsely parallels Interstate 90...

, southwest of the city. The Idaho National Laboratory

Idaho National Laboratory

Idaho National Laboratory is an complex located in the high desert of eastern Idaho, between the town of Arco to the west and the cities of Idaho Falls and Blackfoot to the east. It lies within Butte, Bingham, Bonneville and Jefferson counties...

 (INL) is located east of Arco. Arco is located along the Big Lost River

Big Lost River

The Big Lost River is a major river in the U.S. state of Idaho, about long. It starts in the Rocky Mountains and flows in a generally southeast direction into the Snake River Plain. True to its name, the Big Lost River's surface flow does not reach any larger river, but vanishes into the Snake...

 and is a gateway to the Lost River Valley.
In 1901, the town, then known as Root Hog, moved its borders to place the town at the intersection of two stagecoach routes that crossed Idaho.