Multiple fires sparked off Highway 79 between Green Valley and Paso Picacho, Cal FIRE said Sunday.
The spot fires began burning in Cuyamaca Rancho State Park around 12 p.m., according to fire officials.
Four different fires are currently burning, for a total of approximately 10 to 12-acres.
Cal FIRE said the fires are burning in a light grass and brush area, toward open range.
The portion of Highway 79 in the fire area will be closed for the next several hours, as fire crews respond.
No structures are currently threatened and no evacuations have been ordered.
By 2 p.m. Sunday, Cal FIRE said more than 100 firefighters had been battling the flames and had the brush fires under control.
Check back for updates on this developing story.