A wildfire that sparked Tuesday evening near the Malad Summit was burning 350 acres by Thursday, the Eastern Idaho Interagency Fire Center said.
The fire had previously been reported at 150 acres, but the number grew due to more accurate mapping.
The Welton Fire is burning two miles north of Malad City on Interstate 15 on private land. It did not grow since Tuesday night, when it was spreading south.
Firefighters from the BLM, Forest Service and Oneida County have been fighting the flames using fire engines and air tankers. The fire was 80 percent contained as of Thursday morning, and the agencies hoped to have full containment by 7 p.m. Thursday.
No structures are known to be threatened at this time. Firefighters believe the fire is human-caused.