Columbia River Gorge From Cape Horn, WashingtonAlthough the Columbia River was discoverd by Euro-americans in 1792, when Captain Robert Gray found its mouth and named the river for his ship, the Columbia ??????, It was not until 1805 that the river would be explored by members of the Lewis & Clark Expeditionwho reported on its geology, geography, plants, animals, and peoples. By 1840 it had become the last stage of thelegendary Oregon Trail. Emigrants floated the river from the Dalles to Portland and the Willamette Valley. By 1849, nearly 12,000 people had entered Oregon via this route. Today, tamed by dams, the river is the only sea level passage through the Cascade Range and is usd by industry to transport grain, livestock, lumber, fruits, vegetables, and french-fries; and by boaters, fishermen and windsurfers for recreation.