The August Complex fire was a massive wildfire complex that burned in the Coast Range of Northern California, in Glenn, Lake, Mendocino, Tehama, Trinity, and Shasta Counties. The complex originated as 38 separate fires started by lightning strikes on August 16–17, 2020. Four of the largest fires, the Doe, Tatham, Glade, and Hull fires, had burned together by August 30. On September 9, the Doe Fire, the main fire of the August Complex, surpassed the 2018 Mendocino Complex to become both the single-largest wildfire and the largest fire complex in recorded California history. On September 10, the combined Doe Fire also merged with the Elkhorn Fire (originally a separate incident) and the Hopkins Fire, growing substantially in size. By the time it was extinguished on November 12, the August Complex fire had burned a total of 1,032,648 acres (417,898 ha), or 1,614 square miles (4,180 km), about 1% of California's 100 million acres of land, an area larger than the state of Rhode Island.
The fire largely burned within the Mendocino National Forest, with portions spilling over to the Shasta-Trinity National Forest and Six Rivers National Forest in the north, as well as private land surrounding the forests. Large areas of the Yolla Bolly-Middle Eel Wilderness and Yuki Wilderness had also been burned. Rugged terrain combined with consistent high winds and record heat had complicated firefighting efforts. Although more than 2,900 personnel were deployed to the fire through mid-September, it took almost three months to fully contain the fire. The U.S. Forest Service managed the firefighting effort, with assistance from the California Department of Forestry and Fire Protection.