The Big Grass Fire — which grew to become the largest wildfire in Oregon state history — has been declared 100% contained, crews confirmed this week after more than seven weeks of intensive suppression work across the remote high desert of Malheur County, Oregon and Owyhee County, Idaho.

A Fire of Historic Proportions

The Big Grass Fire ignited on July 23, 2026, approximately 25 miles southwest of Jordan Valley, Oregon. Driven by hot, dry, and windy conditions across the Oregon-Idaho border region, the fire exploded in size through late July and August, surpassing the previous Oregon record — the 2012 Long Draw Fire at 557,028 acres — and ultimately burning 578,637 acres across two states.

At its peak, the fire prompted Level 3 "Go Now" evacuation orders for parts of Owyhee County, Idaho, displacing ranching families and closing major roads across the remote high-desert landscape. The fire's rapid growth — driven by abundant cheatgrass fuel loads and erratic winds — presented extraordinary challenges for incident managers and ground crews.

The Road to Containment

Progress on the Big Grass Fire was slow and uneven. Containment stood at just 21% in late July as the fire continued to grow. A combination of shifting wind events, steep containment improvement at times, and then renewed spread kept crews on the fire for weeks longer than initially anticipated.

  • July 25: 304,237 acres, 21% contained
  • August 4: 343,338 acres, 25% contained
  • August 12: More than 575,000 acres, 35% contained — confirmed largest in Oregon history
  • August 27: 578,637 acres, 93–94% contained
  • September 14: 100% contained

Recovery Underway

With the fire now fully contained, suppression repair work is ongoing across the fire area. Crews have been working to rehabilitate roads, stabilize soils, remove hazard trees, and restore water and soil quality features damaged during suppression activities. Ranchers and landowners have begun the long process of assessing grazing impacts and infrastructure damage across the sprawling fire footprint.

The fire's containment marks a significant milestone for the 2026 Pacific Northwest fire season, removing the largest single active threat from the regional fire map. The Big Grass Fire was managed by a Type 1 Incident Management Team across much of its duration and required the commitment of aircraft, hand crews, engines, dozers, and water tenders across two states.

What's Next

Investigators will continue working to determine the cause of the Big Grass Fire. Cheatgrass and other invasive annual grasses have been identified as a significant factor in the fire's explosive spread — a pattern that has emerged repeatedly across the Great Basin in recent years and that land managers say requires urgent, landscape-scale treatment to reduce long-term fire risk in the region.