The estimated size of the blaze, reported about 3 p.m., was reduced from five to three acres, according to a Twitter post by Alameda County Fire Department.
The fire is located off Crown Court and was initially reported to be threatening homes. As of 3:45 p.m., crews had stopped the blaze's progress, authorities said.
No information was immediately available on the cause of the fire.
No evacuations were ordered.
Crow Canyon Road was closed between Waterford Place/Greenridge Road to Cull Canyon Road, fire officials said.