The 18-acre Mount Si fire was human-caused, the Department of Natural Resources said Monday.
Fire managers consider the fire to be 75 percent contained.
Approximately 80 firefighters DNR, as well as Eastside Fire and Rescue, are fighting the 444th Fire, named because it is burning near 444th Avenue just east of North Bend.
The fire is burning in steep, rocky terrain at the base of Mount Si. Trail closures remain in effect for; Mount Si Trail, Little Si Trail, and the Garden Loop Trail.