NEW CASTLE, Colo. (KKCO/KJCT)-- The Garfield County Sheriff's Office on Tuesday said the Grand Hogback fire is now 50 percent contained.
It was measured at more than 100 acres Tuesday morning, running along County Road 335, just south of New Castle.
Crews have been fighting the fire from the air and the ground since it started on Monday evening.
No structures were threatened and no evacuations were planned.
The sheriff's office said the terrain near the fire is steep.
Crews said they'll be working to make sure the fire doesn't spread east or west to residential areas.
Access along County Road 335 east of New Castle is limited to emergency vehicles and residents to the River Bend subdivision. They said drivers should not stop along I-70 to watch what's happening.
Officials aren't sure what caused the fire, but they estimate the cost to put out the fire will exceed $100,000.
Firefighters from 5 different crews helped get the blaze under control.