The Big Grass Fire, the largest wildfire in modern Oregon history, is approaching full containment after a seven-week campaign that defined the 2026 fire season across the Pacific Northwest. As of this week, the fire stands at 578,637 acres and 94% contained — all but wrapped after burning through a vast swath of southeastern Oregon and southwestern Idaho.

The fire ignited on July 23, 2026, from a lightning strike near the Oregon-Idaho border in the Jordan Valley area. What began as one of hundreds of lightning starts in a dry, wind-driven week grew explosively, torching through drought-parched sagebrush, juniper, and grass fuels across terrain that left crews with limited opportunities to gain the upper hand. By mid-August, it had surpassed every wildfire in Oregon’s recorded history to claim the title of the state’s largest.

Scale of the Fire

To put the Big Grass Fire in perspective:

  • 578,637 acres burned — equivalent to roughly 904 square miles
  • More than twice the size of the Grand Canyon
  • The fire crossed the state line, burning into southwestern Idaho
  • At its peak, it drew resources from across the nation and internationally
  • Governor Tina Kotek declared a state fire emergency as the blaze grew

The Road to Containment

Crews worked more than seven weeks on the perimeter, battling extreme heat, low humidity, and multiple wind events that repeatedly pushed fire through unburned fuel pockets. Rain in early September — along with cooler temperatures and reduced wind — finally allowed firefighters to establish and hold containment lines across the most vulnerable portions of the perimeter.

At 94% contained, mop-up and patrol operations are ongoing. Crews are working to extinguish remaining hotspots, repair dozer lines and hand lines, and stabilize disturbed soils before fall precipitation arrives. The remaining 6% of uncontained perimeter sits in the most remote and rugged sections of the fire area.

A Record-Setting Oregon Season

The Big Grass Fire was the anchor of a historically destructive 2026 fire season for Oregon. The state surpassed 2.5 million acres burned by late August, and the final tally for the season is expected to exceed 4,000 square miles — the most in Oregon’s recorded history. Other major Oregon fires this season include:

  • Crosswhite Fire: 342,923 acres, 92% contained
  • Grasshopper Fire (east of Mount Hood): ~94,000 acres, 96% contained
  • Hagen Fire (Umatilla/Union counties): 61,382 acres, 87% contained
  • Austin Fire (Mount Hood National Forest): ~13,000 acres, 56% contained — still active

As the Big Grass Fire moves toward closure, land managers are already beginning to assess ecological recovery needs, with attention to invasive species control, erosion prevention, and watershed protection across millions of acres of altered landscape.