Lava Hot Springs is a city along the Portneuf River in eastern Bannock County, Idaho, United States.

Located in the mountainous valley of the Portneuf River on the old route of the Oregon Trail and California Trail, the city has become a popular resort location, noted for its numerous hot springs amenable to bathing and a turbulent inner tube run through part of the town.

[5] At the 2010 census there were 407 people in 209 households, including 104 families, in the city.

The primary road through the city is U.S. Route 30 (US 30), which passes just north of the majority of the community.

On the northeast corner of the city is the western end of Old Highway 30, which is a former routing of US 30 that runs parallel to and just south of the Union Pacific Railroad (UP) tracks (formerly Oregon Short Line)[10] around the north end of the Fish Creek Range.

The current routing of US 30 via Fish Creek Summit reduced the distance between Lava Hot Springs and Soda Springs by about 11 miles (18 km), but bypassed the city of Bancroft.

Notwithstanding, the rerouting still created a more direct route between Lava Hot Springs and Bancroft (via Central Road), reducing driving distance between the cities by about 5.5 miles (8.9 km).