The fire threatened "a couple dozen homes" in the Redwood Parkway and Skyline Drive area, Tweedy said. No homes were damaged.
The fire burned on a hill toward the homes along one side of a two-mile trail through the park, Tweedy said. It was reported around 1 p.m. There is no electricity or other fire source in the area and Tweedy said the most probable cause is arson, through the blaze is still under investigation.
Tweedy said there have been previous fires in the area frequented by pedestrians.
All available Vallejo firefighters responded and Benicia, Crockett, American Canyon, Cordelia, Cal Fire and Solano County firefighters provided mutual aid, Tweedy said.
There were around 50 firefighters at the scene where temperatures were in the high 80s with winds 15 mph and 20 mph, Tweedy said.
Firefighters will be mopping up the scene until around 7 p.m. or 8 p.m., Tweedy said.