Idaho State Highway 31 is a 21.025 miles (33.84 km) north-south state highway

State highway

State highway, state road or state route can refer to one of three related concepts, two of them related to a state or provincial government in a country that is divided into states or provinces :#A...

 in the eastern part of the U.S. state

U.S. state

A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...

 of 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....

. SH-31 runs from U.S. Route 26

U.S. Route 26

U.S. Route 26 is an east–west United States highway. It started in Ogallala, Nebraska, and gradually grew to reach the West Coast in Oregon. When the U.S. highway system was first defined, it was limited to Nebraska and Wyoming; by the 1950s, it continued into Idaho and Oregon. The...

 in Swan Valley

Swan Valley, Idaho

Swan Valley is a city in Bonneville County, Idaho, United States. It is part of the Idaho Falls, Idaho Metropolitan Statistical Area. The population was 213 at the 2000 census.-Geography:Swan Valley is located at ....

 north to Idaho State Highway 33 in Victor

Victor, Idaho

Victor is a city in Teton County, Idaho, United States. The population was 840 at the 2000 census. It is part of the Jackson, WY-ID Micropolitan Statistical Area.-Geography:Victor is located at...

. The highway is maintained by the Idaho Transportation Department

Idaho Transportation Department

The Idaho Transportation Department is the State of Idaho governmental organization responsible for the current transportation infrastructure. This includes ongoing operations and maintenance; as well as planning for future needs of the state and its citizens...

.

Route description

SH-31 begins at an intersection with U.S. Route 26

U.S. Route 26

U.S. Route 26 is an east–west United States highway. It started in Ogallala, Nebraska, and gradually grew to reach the West Coast in Oregon. When the U.S. highway system was first defined, it was limited to Nebraska and Wyoming; by the 1950s, it continued into Idaho and Oregon. The...

 in Swan Valley

Swan Valley, Idaho

Swan Valley is a city in Bonneville County, Idaho, United States. It is part of the Idaho Falls, Idaho Metropolitan Statistical Area. The population was 213 at the 2000 census.-Geography:Swan Valley is located at ....

. The highway leaves Swan Valley to the northeast, crossing Rainey Creek and entering a rural part of Bonneville County

Bonneville County, Idaho

Bonneville County is a county located in the U.S. state of Idaho. As of the 2010 census, the county had a population of 104,234. Its county seat and largest city is Idaho Falls...

. The route turns north before heading northwest, then turning north again. After crossing Pine Creek, SH-31 heads northeast and enters Targhee National Forest. The highway enters a mountainous region at this point, passing to the south of Stouts Mountain. SH-31 crosses North Pine Creek before crossing into Teton County

Teton County, Idaho

Teton County is a county located in the U.S. state of Idaho. Established in 1915, it was named after the Teton Mountains. As of the 2000 Census the county had a population of 5,999...

. It passes the Pine Creek Campground before leaving Targhee National Forest. The highway enters a rural area and begins a more easterly course. It turns northeast into Victor

Victor, Idaho

Victor is a city in Teton County, Idaho, United States. The population was 840 at the 2000 census. It is part of the Jackson, WY-ID Micropolitan Statistical Area.-Geography:Victor is located at...

, then turns east, becoming Center Street. SH-31 terminates at Idaho State Highway 33 in central Victor.

Major intersections

County	Location	Mile	Junction	Notes
Bonneville Bonneville County, Idaho Bonneville County is a county located in the U.S. state of Idaho. As of the 2010 census, the county had a population of 104,234. Its county seat and largest city is Idaho Falls...	Swan Valley Swan Valley, Idaho Swan Valley is a city in Bonneville County, Idaho, United States. It is part of the Idaho Falls, Idaho Metropolitan Statistical Area. The population was 213 at the 2000 census.-Geography:Swan Valley is located at ....	0.000
Teton Teton County, Idaho Teton County is a county located in the U.S. state of Idaho. Established in 1915, it was named after the Teton Mountains. As of the 2000 Census the county had a population of 5,999...	Victor Victor, Idaho Victor is a city in Teton County, Idaho, United States. The population was 840 at the 2000 census. It is part of the Jackson, WY-ID Micropolitan Statistical Area.-Geography:Victor is located at...	21.025