Near Ontario in Malheur County, Oregon — The American West (Northwest)
Malheur Butte
Inscription.
Between 20 and 15 million years ago, the region from north-central Washington to northeastern California experienced a series of volcanic eruptions and basalt lava floods that covered thousands of square miles. These ancient lava floods often dammed streams, creating lakes and swamps that may have lasted for millions of years before filling with sediment or draining as erosion slowly lowered their outlets. The western Snake River plain contained many such lakes and geologists believe that between 8 and 2 million years ago, “Lake Idaho” covered much of central eastern Oregon. Sediment deposited in this lake once probably covered Malheur Butte, and during the last 2 million years the Malheur River and other eroding forces slowly exposed and shaped todays landmark.
Although Malheur Butte has been inactive for millions of years, Malheur County is still alive with geothermal activity in the form of hot springs. Today, Oregon Trail Mushrooms uses geothermal energy at their processing plant in Vale, and efforts are being made to further utilize this unique energy source throughout the county.
Erected by Oregon Economic Development Department.
Topics. This historical marker is listed in this topic list: Natural Features.
Location. 43° 59.136′ N, 117° 5.976′ W. Marker is near Ontario, Oregon, in Malheur County. It is on Thundered Boulevard (U.S. 26) near Lee Road. Touch for map. Marker is at or near this postal address: 950 Central Oregon Highway, Ontario OR 97914, United States of America. Touch for directions.
Regionally, this marker is in Eastern Oregon. It is also in the American Mountain West and in the Lewis & Clark Corridor. Globally, it is in North America, the Pacific Rim, the Western Hemisphere, the Western World, and the Anglosphere.
Other nearby markers. At least 8 other markers are within 7 miles of this marker, measured as the crow flies: Malheur County's Oregon Trail Heritage (here, next to this marker); First People of the Land (approx. 6½ miles away); Under the Wagon Cover (approx. 6½ miles away); Imagine a Day's Journey (approx. 6½ miles away); In Search of a Dream (approx. 6½ miles away); Cutoff Fever (approx. 6.6 miles away); Vale Oregon Trail Kiosk (approx.
6.8 miles away); John D. Henderson (approx. 6.8 miles away).
Credits. This page was last revised on August 18, 2017. It was originally submitted on August 18, 2017, by Barry Swackhamer of Brentwood, California. This page has been viewed 1,025 times since then and 80 times this year. Photos: 1, 2. submitted on August 18, 2017, by Barry Swackhamer of Brentwood, California.

