A grass fire near the Alameda County/San Joaquin County border early this morning consumed about 25 acres of vegetation but didn't damage any structures, a Cal Fire dispatcher said.
The fire was reported just after 1 a.m. near Grant Line Road north of Interstate Highway 580 in the area of the Altamont Pass, California Highway Patrol Officer Ralph Caggiano said.
Firefighters from multiple agencies, including the Alameda County Fire Department and the Tracy Fire Department, contained the flames by 2:50 a.m.
No injuries were reported. The cause of the fire remains under investigation.