At 3,100 feet elevation, Satus Pass is the highest pass across the Horse Heaven Hill, also known as the Simcoe Mountains. It offers an excellent view of the remnants of million year-old volcanic activity in a series of ridges. The hills were formed about five million years ago when magma began pushing up into the crust of the earth below this part of the land. The magma eventually broke through to the surface and began erupting as lava flows and cinder cones. The volcanic activity persisted until about a million years ago when the last of the lava poured down off the Columbia Hills and into the Columbia River. Satus Pass offers an excellent view of the remnants of this activity in a series of ridges that trend mainly in an east-west direction.
