103 million-year-old dinosaur bone found in Oregon The bone was found during a 12-day dig at a University of Oregon dig site near Mitchell, Ore. Author: Devon Haskins Updated: 6:34 PM PDT July 8, 2021 MITCHELL, Ore. — Dinosaurs roamed the earth hundreds of millions of years ago, but their bones aren't commonly found in Oregon. The reason? Well, the state was covered in water for most of the dinosaur ages. In fact, the first dinosaur bone found in Oregon was only discovered about six years ago. Last year, more bone fragments were found while digging through loose rock near the town of Mitchell in Central Oregon.