Course Snake River

the snake river exits jackson lake , winds southwards through jackson hole

formed confluence of 3 tiny headstreams on southwest flank of 2 oceans plateau in western wyoming , yellowstone national park, snake starts out small river flowing west , south jackson lake. first 50 miles (80 km) run through valley of jackson hole, cuts between teton range , continental divide. snake takes large bend northwest through snake river canyon, cutting through snake river range , eastern idaho, receiving first hoback , greys rivers before entering palisades reservoir. there met salt river @ mouth of star valley. after passing through palisades dam, snake river flows through snake river plain, vast physiographic province extending through southern idaho across massif of rocky mountains , underlain snake river aquifer, 1 of productive aquifers in united states.

southwest of city of rexburg, snake receives right henrys fork, called north fork of snake river. confluence henrys fork takes river southwards through downtown idaho falls, rounding fort hall indian reservation , american falls reservoir, receiving portneuf river. portneuf river valley overflow channel in last glacial period carried floodwaters pluvial lake bonneville snake river plain, carving out many topographic features , altering snake river landscape. snake river resumes journey westwards, enters snake river canyon of idaho, drops on shoshone falls, waterfall marks historical upriver limit of migrating salmon, , passing under perrine bridge. close twin falls, snake approaches southernmost point in entire course, after starts flow northwest.

the clearwater river (left) joins snake river (center) @ lewiston

shortly after passes within 30 miles (48 km) of idaho state capital of boise, river surges past state border oregon, close meets owyhee, boise , payette rivers. snake river begins define 200-mile-long (320 km) idaho–oregon state border, follows river hells canyon, steep , spectacular gorge cuts through salmon river mountains , blue mountains of idaho , oregon. hells canyon 1 of rugged , treacherous portions of course of snake river, pioneers on oregon trail , steamboat operators in 19th century had great difficulty negotiating. there hundreds of rapids in hells canyon, of have been stilled 3 dams of hells canyon hydroelectric project: hells canyon, oxbow, , brownlee.

the salmon river, largest tributary of snake river, meets in 1 of remote areas of entire course, @ halfway point in hells canyon. there, snake crosses washington , idaho, receiving grande ronde river west before receiving clearwater river @ lewiston, uppermost major city on navigable stretch of snake. snake leaves hells canyon , spreads low-lying palouse hills of eastern washington, lower snake river project s 4 dams have transformed snake river series of reservoirs. confluence of snake , columbia rivers has been submerged in lake wallula, reservoir of mcnary dam. columbia river flows 325 miles (523 km) further west pacific ocean, cutting through cascade range way of columbia river gorge.