The Columbia River Gorge is a spectacular river canyon cutting the only sea-level route through the Cascade Mountain Range. It is 80 miles long and up to 4,000 feet deep with the north canyon walls in Washington State and the south canyon walls in Oregon State. Hiking, mountain biking, windsurfing, camping, fishing, boating, wildlife watching, birding, wildflower watching, photography, picnicking, rock climbing. You can do all this and more in the Columbia River Gorge National Scenic Area. Through millenniums of geologic events, waterfalls have found their home in the Columbia River Gorge. A visit to the area is not complete without a visit to its breathtaking waterfalls. Multnomah Falls is the second highest year-round waterfall in the United States. Though Multnomah Falls is grand and popular, all of the falls in the Gorge are special and breathtaking. For over 31,000 years, the Columbia River Gorge has supported flourishing civilizations. Evidence of the Folsom and Marmes people, who crossed the Great Continental Divide from Asia, were found in archaeological digs. Excavations at Five Mile Rapids, a few miles east of The Dalles, show humans have occupied this ideal salmon fishing site for more than 10,000 years. The Columbia River Plateau was created by a series of basalt flows. Six to seventeen million years ago, the flows covered 164,000 square kilometers portions of northeast Oregon, southwest Washington and western Idaho.