Firefighters from Imperial County, Calipatria, El Centro, Calexico, Holtville, Naval Air Facility El Centro and a crew from Centinela State Prison responded to the scene.
They joined crews from the Yuma Fire Department, Rural Metro of Yuma, the U.S. Bureau of Land Management, the Bureau of Indian Affairs and the U.S. Marine Corps.
The fire spread along the river's edge until it reached the Fourth Avenue bridge along Interstate 8.
There were reports the fire leapt the freeway and burned a trailer on the south side of I-8, fire officials reported.
Seaman said the California Highway Patrol had to close a section of Interstate 8 because of the flames.
Fire crews continued to battle the blaze until midnight.
Seaman said by that time the fire was extinguished, most crews from the Imperial Valley were released from the scene. He said crews from Yuma remained on scene through Sunday morning to prevent flare-ups.
Seaman said one Rural Metro firefighter suffered heat exhaustion as temperatures soared past 100 degrees. There were no other reports of injuries, Seaman said.
El Centro Fire Department Capt. Domingo Enriquez said the first concern for firefighters was protecting the lives of those who live in the area and their property.
He also said firefighters had to protect themselves.
"It's just damn hot out there," he said. "There is no other way around it. The heat doesn't let up."
He said the heat and danger to firefighters could have been one reason the fire was classified as a third-alarm blaze, which meant fire crews from throughout the Valley were summoned.
Staff Writer Darren Simon can be reached at 337-4082.