Description

The Boring Lava Field is a Plio-Pleistocene volcanic field of cinder cones, small shield volcanoes, and lava flows in the northern Willamette Valley of the U.S. state of Oregon and adjacent southwest Washington. The volcanic field is named for the town of Boring, Oregon, located 12 miles (20 km) southeast of downtown Portland and on the edge of the densest cluster of volcanic vents. The zone became volcanically active about 2.7 million years ago, with long periods of eruptive activity interspersed with quiescence. Its last eruptions took place about 57,000 years ago at the Beacon Rock cinder cone volcano. The individual volcanic vents of the field are considered extinct, but the field itself is not.