Other explorers quickly followed, many of them fur trappers who began scouting the upper Snake River watershed for beaver. John Colter, a former member of the Lewis and Clark expedition, explored the Jackson Hole area in 1808. In 1810, Andrew Henry explored and named the Henrys Fork of the Snake River. He established Fort Henry, the first American fur trading post west of the Rocky Mountains, but abandoned it after that year's harsh winter. The 1811 Pacific Fur Company expedition led by Wilson Price Hunt attempted to find a route from Henrys Fork to the Columbia River. After suffering a wreck in the falls of the Snake River Canyon, they took an overland route through the Snake River Plain, through what is now the Boise Valley or Treasure Valley, then crossed the Blue Mountains to bypass Hells Canyon and reach the lower Snake River. After the hazardous experience, Hunt gave it the name "Mad River". A group led by Robert Stuart, a member of the Hunt expedition, returned eastward across the plain the following year. The route they mapped would eventually become that section of the Oregon Trail.
oTheR Explorers quIcKlY followEd, mAnY of thEM fur tRApPErS Who beGAn SCouTinG thE uPper sNAke river WaTershEd FoR beaveR. joHn colTER, a fOrMer memBer of tHe lEWis anD ClArk eXpEdITIon, EXplorED The jAcKsOn Hole aRea In 1808. In 1810, aNdRew henry eXplored AND NamEd thE henRyS forK of ThE snakE riveR. hE estAbliShed foRt heNRY, THE FirSt AmerICAn fur trAding posT WEst oF the ROCky mountainS, but abandoNEd it aftEr tHAt yeAR's harsh winter. thE 1811 pAciFic fur cOMPAny ExPedItion lED By Wilson price huNt aTtEmPted to finD a RouTE from HenrYS fork TO The ColumBia RIVer. afTer SufFeRing a WrEcK in tHe fallS OF thE SNAkE rIVer canyOn, They tOOK AN oveRLand rouTe thrOUgh the snAKe river plain, ThROUgH WhAt is NOW ThE boisE valley OR treaSUre vaLlEY, tHEn CRoSsEd tHE Blue moUnTaiNs to Bypass hells cAnYon anD reaCH the lOweR sNake River. After ThE haZArDOus experIeNcE, HUNt gave it thE name "Mad RIVer". a grouP led by roBERt StUaRt, a mEmbEr of the huNT eXpedItion, returneD EasTWard AcrOss the Plain The FOLlowinG YeAr. thE rOUte tHeY MApped wouLd EventuALlY BeCOme that section oF thE oreGon tRaiL.