"The Columbia River Gorge is a canyon of the Columbia River in the Pacific Northwest of the United States. Up to 4,000 feet (1,200 m) deep, the canyon stretches for over 80 miles (130 km) as the river winds westward through the Cascade Range forming the boundary between the State of Washington to the north and Oregon to the south. The wide range of elevation and precipitation in the gorge creates a diverse collection of ecosystems from the temperate rain forest at Oneonta Gorge (with an average annual precipitation of 75 inches (1,900 mm)) to the Celilo grasslands (with average annual precipitation 12 inches (300 mm). The gorge also contains a high concentration of waterfalls, with over 90 waterfalls on the Oregon side of the gorge alone. Many are along the Historic Columbia River Highway, including the notable 620-foot (190 m)-high Multnomah Falls." wikipedia