Firefighters made headway building a containment line near the Eel River against a group of wildfires burning in the thick forest of northeastern Mendocino County.

The fires grew by about 600 acres overnight, reaching 11,900 acres, although cooler weather and an increase in relative humidity continued aiding the firefight, Cal Fire officials said early Thursday. The fire was 55 percent contained.

Flames burning interior portions of the fire were still visible from portions of Highway 101 near Laytonville and Leggett, spokeswoman Julie Cooley said. Heavy smoke remained throughout the Ukiah Valley.

The fire, sparked by lightning July 30, was now mainly surrounded by cleared ground.

Officials downgraded an evacuation order to an evacuation warning for Camp Seabow, Bowman Ranch, Hunt Ranch, Tan Oak Park, Elk Creek and Mad Creek.

Evacuation orders remained for areas south of Highway 101, west of Cummings Road to the small tourist town of Leggett. These areas include: The Hermitage, Big Bend and Camp St. Michael.

Nearly 2,000 personnel from agencies throughout Northern California were battling the fire aided by 13 helicopters. The fire’s cost was estimated at $27 million.

You can reach Staff Writer Julie Johnson at 521-5220 or On Twitter @jjreport.