The Big Grass Fire has officially become the largest wildfire in Oregon state history, burning more than 513,000 acres across the remote high desert straddling the Oregon-Idaho border as of mid-August 2026. The fire, which started from a lightning strike on July 23 approximately 25 miles southwest of Jordan Valley in Malheur County, has spread dramatically across sage-covered rangeland and has shown little sign of slowing down.

Fire Details

  • Start date: July 23, 2026
  • Location: Approximately 25 miles southwest of Jordan Valley, Oregon
  • Size: 513,437+ acres
  • Containment: Approximately 36 percent
  • Cause: Lightning
  • Cost to date: Over $41.3 million
  • Personnel assigned: 1,304 (Type 1 Complex Incident Management Team)

A Historic Burn

Before this season, Oregon's fire record books were dominated by large 20th-century burns in forested terrain. The Big Grass Fire is notable not only for its size but for how quickly it grew across the arid rangeland of southeastern Oregon and southwestern Idaho. With sparse road access, rolling terrain, and vast acreages of dry native grasses and sagebrush, suppression crews have faced extraordinary logistical challenges.

Evacuation orders at the GO (Level 3) status were issued in late July as the fire crossed into southwestern Idaho and threatened ranches and rural communities. The fire continues to burn into Idaho, making it a multi-state incident of the highest complexity.

Impacts on Ranching and Public Lands

The scale of the fire has devastated rangeland across Malheur County and Washington County, Idaho. Hay fields and livestock pastures have burned, and access closures remain in effect across large portions of the affected public lands. Both the Tartar Fire near Weiser, Idaho and the Big Grass Fire have prompted closures affecting hunters ahead of early hunting seasons, according to Idaho Fish and Game officials.

Fence lines, water infrastructure, and grazing allotments have been damaged across the fire's enormous footprint. Recovery of the affected rangeland and sage-steppe ecosystem is expected to take years, with concerns about invasive cheatgrass establishing rapidly in burned areas — a dynamic that can increase future fire risk dramatically.

Firefighting Strategy

With 1,304 personnel and a Type 1 Complex Incident Management Team in command, crews are employing a combination of direct and indirect suppression strategies. In terrain where direct attack is feasible, crews are working to establish and hold control lines. In remote areas, aerial resources have been used extensively to slow the fire's spread and protect structures.

Officials caution that the Big Grass Fire will continue burning until significant precipitation arrives or containment lines are successfully established across the remaining perimeter. Malheur County and the surrounding region should continue to monitor conditions and heed any evacuation orders that may be issued or expanded.

What This Means for Oregon

The Big Grass Fire is a defining event of the 2026 fire season, underscoring the vulnerability of Oregon's eastern range country to large, fast-moving fires during periods of drought and high heat. State and federal agencies are coordinating closely with local communities, tribal governments, and neighboring states to manage the ongoing response.