Malheur Butte is an extinct volcano in eastern Oregon that rises prominently from the plains of Malheur County, standing as a distinct landmark in the western Snake River plain. It formed within a region transformed by eruptions and immense basalt lava floods between 20 and 15 million years ago. Geologists believe it was later buried by sediments from Lake Idaho between 8 and 2 million years ago, then gradually exposed and shaped by the Malheur River and other erosive forces over the past 2 million years. Its name, from French for misfortune, is linked to the nearby river and an 1826 account by trader Peter Skene Ogden.