The Boring Lava deposits lie west of the town of Boring. The Global Volcanism Program lists its highest elevation as , at Larch Mountain, with most vents reaching an elevation of . Located in the Portland Basin, the field consists of monogenetic volcanic cones that appear as hills throughout the area, reaching heights of above their surroundings. The collection includes more than 80 small volcanic edifices and lava flows in the Portland-Vancouver metropolitan area, with the possibility of more volcanic deposits buried under sedimentary rock layers. The borders for the Boring Lava Field group are clear, except on the eastern side where distinguishing between Boring deposits and those from the major Cascade arc are less clear; many geologists have arbitrarily placed the eastern border at a longitude of 122 degrees west. In total, the Boring Lava Field covers an area of about , and it has a total volume of .