The River Fire started in Placer County on August 4, 2021 at 1:59 PM and burned a total of 2,619 acres. 142 structures were destroyed in Placer and Nevada Counties. The fire was contained on August 13, 2021.

CAL FIRE/Placer County Fire Department Investigators were immediately dispatched to the River Fire and began working to determine the origin and cause of the fire. This is a meticulous process requiring Investigators to examine credible information to conclusively identify a factual cause.

It has been determined that the River Fire started in the overnight camping area of the Bear River Campground and was human caused. This is an active case, and CAL FIRE investigators will continue to work on determining the specific details leading to the cause of the fire.