Firefighters responded to a brush fire at the base of Cerro San Luis late Thursday morning.
The fire was reported just before 11 a.m. near the Serrano Heights Trailhead, on the Foothill Blvd. side of the mountain.
San Luis Obispo City Firefighters say it burned approximately one acre before crews got it under control.
The cause of the fire is under investigation.
Firefighters say no structures were damaged.
A short distance away, a fire burned less than a quarter-acre of brush along Los Osos Valley Rd. near Foothill Blvd.
It was reported shortly before 11:30 a.m.