The Nees Fire started burning Wednesday afternoon near Interstate 5 and West Nees Avenue. That's located about 16 miles south of Los Banos and about 18 miles west of Firebaugh.
The fire started in Merced County but quickly spread over the county line and into Fresno.
Officials said the fire spread very quickly due to winds. Aircraft and ground crews have been used to fight the fire.
At this time, no evacuations have been ordered and no structures are threatened. Fire crews are working to protect some nearby power lines.