Mount Borah, Idaho’s highest peak at 12,662 feet, is named for William E. Borah, who served in the United States Senate from 1907 until his death in 1940. In the past billion years, ten or a dozen large but shallow inland seas covered this area, becoming a graveyard for countless generations of sea creatures whose bones, shells, coral, and microscopic remains accumulated through the eons into a clay-and-limestone deposit thousands of feet thick. During the past 10 or 20 million years, part of this deposit was thrust upward into the towering ridge seen here.