Big Grass Fire Becomes Oregon's Largest in History at 579,000 Acres

The Big Grass Fire burning along the Oregon-Idaho border has cemented its place in the history books as the largest wildfire ever recorded in Oregon, having scorched approximately 579,134 acres of high desert rangeland in southeastern Oregon and southwestern Idaho. As of August 18, 2026, the fire is 82% contained — a significant improvement from earlier in the season — but active fire behavior continues in isolated areas, and full containment has not yet been achieved.

Fire Overview

The Big Grass Fire ignited in the Jordan Valley area of Malheur County, Oregon, and rapidly spread into Owyhee County, Idaho. The fire burned with extraordinary speed through the dry sagebrush steppe and grass fuels characteristic of the region, driven by persistent hot, dry winds and record low relative humidity readings. At its peak, the fire threatened 737 structures along the Oregon-Idaho border and prompted sweeping evacuation orders across a vast rural area.

Evacuation Orders Remain in Effect

A Level 3 "Go" evacuation order remains in effect for portions of Owyhee County, Idaho, covering a large swath of remote rangeland near Jordan Valley. The order boundary runs approximately 1.2 miles east of Jordan Valley along the Idaho state line, north to Baxter Creek Basin, east to Sommer Camp Mountain, southeast to the Wickahoney Road and Riddle Ranch Road intersection, and south along the reservation boundary to the Nevada state line.

Residents and ranchers within the order area are required to leave immediately and should not return until the order is officially downgraded by Owyhee County emergency management. Additional Level 1 (Ready) and Level 2 (Set) notices remain in effect for surrounding areas, including parts of Pleasant Valley, Flint Creek Road, Triangle, and Antelope-Ridge Road.

Firefighting Progress

Fire managers report that crews have successfully secured containment lines across the majority of the fire perimeter, using a combination of bulldozers, hand crews, and aerial assets. The improved 82% containment figure reflects weeks of sustained work by hundreds of firefighters, many of whom operated in extreme heat exceeding 100 degrees Fahrenheit.

However, officials warn that pockets of uncontrolled fire remain, particularly in areas with rugged terrain or heavy fuel loads. Dry conditions and shifting winds could still allow the fire to push into unburned areas if containment lines are compromised.

Political and Historical Significance

The Big Grass Fire has drawn national attention and political response. U.S. Sen. Jeff Merkley (D-OR) cited the fire as evidence of the urgent need to address wildfire risk and raised concerns about the impact of recent Forest Service budget and staffing reductions. Interior Secretary Doug Burgum and Agriculture Secretary Brooke Rollins both visited the Northwest region to assess damages.

The fire has destroyed critical rangeland used by cattle ranchers and has raised questions about livestock losses and long-term recovery of native bunchgrass ecosystems. Recovery of burned rangeland in the Great Basin region typically takes multiple years and can be complicated by invasive species colonization.

What Residents Should Know