The blaze, dubbed the Keenbrook Fire, was first reported around 11 a.m. near Cajon Boulevard. Around 250 fire personnel from the San Bernardino County Fire Department and the San Bernardino National Forest Service battled the blaze.
The blaze charred approximately 50 acres, fire officials said. An advisory evacuation was issued for the Mathews Ranch area as well as for structures north of the fire, San Bernardino National Forest Service officials said.
Initially, just the southbound 15 Freeway was shut down near Highway 138. The northbound 15 Freeway was shut down a short time later, as was the northbound 215 Freeway at Palm/Kendall, according to Caltrans.
Both directions of the 15 Freeway were reopened with some restrictions on the southbound side, Caltrans tweeted around 2:40 p.m., adding that the northbound 215 Freeway was also reopened.
Cajon Boulevard was also later reopened.
At about 5 p.m., the San Bernardino County Fire Department said all advisory evacuations were lifted. Containment was at 50 percent, with some small flare ups still happening during the mop-up.
The cause of the blaze was not known.