Oregon · Active · 579,134 acres
Big Grass Fire, Oregon
579,134
Acres reported
82%
Contained
+686
Acres since yesterday
Last updated · refreshed every 15 minutes from the NIFC WFIGS feed · awareness only — follow local authorities
Update ·
As of Aug 18, 2026, 09:15 UTC, the Big Grass Fire is listed as active at 579,134 acres, 82% contained, in Malheur County, Oregon.
Since Aug 17, 2026, 09:00 UTC: +686 acres.
The most recent mapped perimeter (Aug 17, 2026, 23:37 UTC) covers 579,135 acres; the mapped perimeter has been updated 60 times since the fire began.
No satellite heat detections matched to this incident in the last 24 hours (last one Aug 13, 2026, 10:26 UTC).
Big Grass Fire map
The most recent mapped perimeter (solid) and the previous day's perimeter (dashed), with the reported point of origin.
Latest perimeter Previous perimeter · Perimeters come from the WFIGS interagency perimeter service and are usually mapped once a day; the mapped area can differ from the reported acreage.
Key facts
- Size
- 579,134 acres
- Containment
- 82%
- Status
- Active
- Discovered
- Jul 23, 2026
- Location
- Malheur County, Oregon
- Origin point
- 42.6498, -117.3034
- Peak reported size
- 582,226 acres
- Perimeter mapped
- Aug 17, 2026 (10 hours ago)
- Satellite heat, 24 h
- none matched
Nearest towns
Distances are from the reported point of origin, not from the fire’s edge (see the perimeter map for the current extent).
- Marsing, ID
- Homedale, ID
- Nampa, ID
- Kuna, ID
- Wilder, ID
Other fires nearby
- Gerdie Fire
Big Grass Fire daily history
The largest size and containment reported each UTC day, from our 15-minute archive of the federal feed (first seen Jul 23, 2026, 21:00 UTC).
| Day (UTC) | Reported size | Change | Contained |
|---|---|---|---|
| Aug 18, 2026 | 579,134 acres | +686 | 82% |
| Aug 17, 2026 | 578,448 acres | −3,778 | 71% |
| Aug 16, 2026 | 582,226 acres | 0 | — |
| Aug 15, 2026 | 582,226 acres | +901 | — |
| Aug 14, 2026 | 581,325 acres | +1,964 | — |
| Aug 13, 2026 | 579,361 acres | +4,018 | — |
| Aug 12, 2026 | 575,343 acres | +21,371 | — |
| Aug 11, 2026 | 553,972 acres | 0 | — |
| Aug 10, 2026 | 553,972 acres | +49,587 | — |
| Aug 9, 2026 | 504,385 acres | +62,069 | — |
| Aug 8, 2026 | 442,316 acres | +51,416 | — |
| Aug 7, 2026 | 390,900 acres | +31,989 | — |
| Aug 6, 2026 | 358,911 acres | +12,233 | — |
| Aug 5, 2026 | 346,678 acres | +4,326 | — |
| Aug 4, 2026 | 342,352 acres | +5,573 | — |
| Aug 3, 2026 | 336,779 acres | +29,261 | — |
| Aug 2, 2026 | 307,518 acres | +3,289 | — |
| Aug 1, 2026 | 304,229 acres | +1,172 | — |
| Jul 31, 2026 | 303,057 acres | +1,485 | — |
| Jul 30, 2026 | 301,572 acres | +13,452 | — |
| Jul 29, 2026 | 288,120 acres | −11,880 | — |
| Jul 28, 2026 | 300,000 acres | +20,000 | — |
| Jul 27, 2026 | 280,000 acres | 0 | — |
| Jul 26, 2026 | 280,000 acres | +150,000 | — |
| Jul 25, 2026 | 130,000 acres | +100,000 | — |
| Jul 24, 2026 | 30,000 acres | +25,000 | — |
| Jul 23, 2026 | 5,000 acres | — | — |
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Big Grass Fire questions, answered from the data
How big is the Big Grass Fire?
As of Aug 18, 2026, 09:15 UTC, the Big Grass Fire is reported at 579,134 acres (peak reported size 582,226 acres). Since Aug 17, 2026, 09:00 UTC: +686 acres.
Is the Big Grass Fire contained?
Not fully. It was 82% contained as of Aug 18, 2026, 09:15 UTC. Containment is the share of the fire's edge that has a control line; it is reported by the incident team and can lag the ground situation.
Where is the Big Grass Fire?
The reported point of origin is at 42.6498, -117.3034 in Malheur County, Oregon. Nearest towns: Marsing (67 mi N), Homedale (69 mi N), Nampa (72 mi NE). The map on this page shows the most recent mapped perimeter.
Is the Big Grass Fire still burning?
The federal feed still lists it as active as of Aug 18, 2026, 09:15 UTC; no satellite heat detections were matched to it in the last 24 hours.
Where do I find evacuation orders for the Big Grass Fire?
From the county sheriff and local emergency management, not from this site. Check the official Oregon sources on our Oregon page and your county’s alert system. FireRiskHere is for awareness only.
How current is this page?
The numbers come from the National Interagency Fire Center's WFIGS incident feed and the WFIGS perimeter service, refreshed every 15 minutes, plus NASA FIRMS satellite detections hourly. This page was last updated Aug 18, 2026, 09:15 UTC. Acreage and containment are what the incident team reports and can lag by hours.
About this page
This page is generated automatically for every wildfire whose reported size reaches 1,000 acres, from FireRiskHere’s archive of the National Interagency Fire Center’s WFIGS incident feed (captured every 15 minutes), the WFIGS interagency perimeter service, and NASA FIRMS satellite detections. It stays online after the fire is contained as a record of the incident. Nothing here is an official notice — for evacuation orders and road closures follow your county sheriff and local emergency management. How the site works →