The Station Fire was fully contained Friday after it burned in the San Gabriel Mountains for 52 days.
The largest wildfire in county history started Aug. 26. Two firefighters were killed and 89 homes were destroyed.
Forest Service officials said the 250-square-mile was 98-percent contained in late September. A wet weather system moved through the region last week and crews hiked into the San Gabriel Wilderness area.
The arson blaze started near a ranger station.
A felony charge was filed Monday against a transient accused of setting a small blaze that broke out less than a week before -- and about six miles away from -- the massive Station Fire in the Angeles National Forest.
Babatunsin Olukunle, 25, was taken into custody last Thursday by deputies from the Lancaster station, three days after the Sheriff's Department held a news conference to announce that he'd been seen in the area of the Aug. 22 blaze dubbed the Lady Bug fire.
He was due to be arraigned at the Pasadena courthouse Monday afternoon on one felony count of unlawfully causing a fire in a national forest, according to sheriff's and district attorney's officials.
The estimated cost of the Station Fire as of Oct. 15 was $95.2 million.