, ▁the ▁role ▁of ▁the ▁river ▁as ▁link ▁between ▁Lake ▁Michigan ▁and ▁the ▁Mississippi ▁was ▁extended ▁into ▁the ▁era ▁of ▁modern ▁industrial ▁sh ipping . ▁ ▁The ▁Illinois ▁now ▁forms ▁the ▁basis ▁for ▁the ▁Illinois ▁Water way . ▁ ▁H ydro graph y ▁The ▁Illinois ▁River ▁is ▁formed ▁by ▁the ▁confl u ence ▁of ▁the ▁K ank ake e ▁River ▁and ▁the ▁Des ▁Pla ines ▁River ▁in ▁eastern ▁Grund y ▁County , ▁approximately ▁ ▁south west ▁of ▁J ol iet . ▁This ▁river ▁flows ▁west ▁across ▁northern ▁Illinois , ▁passing ▁Morris ▁and ▁Ott awa , ▁where ▁it ▁is ▁joined ▁by ▁the ▁M azon ▁River ▁and ▁Fox ▁River . ▁At ▁La S alle , ▁the ▁Illinois ▁River ▁is ▁joined ▁by ▁the ▁Verm il ion ▁River , ▁and ▁then ▁it ▁flows ▁west ▁past ▁Peru , ▁and ▁Spring ▁Valley . ▁In ▁sout he astern ▁Bureau ▁County ▁it ▁turns ▁south ▁at ▁an ▁area ▁known ▁as ▁the ▁" Gre at ▁B end ", ▁flow ing ▁south west ▁across ▁western ▁Illinois , ▁past ▁La con , ▁Henry ▁and ▁dow nt own ▁Pe oria , ▁the ▁chief ▁city ▁on ▁the ▁river . ▁ ▁South ▁of ▁Pe oria , ▁the ▁Illinois ▁River ▁goes ▁by ▁East ▁Pe oria ▁and ▁Cre ve ▁Co eur ▁and ▁then ▁P ek in ▁in ▁T az ew ell ▁County . ▁It ▁is ▁then ▁joined ▁by ▁the ▁Mack ina w ▁River ▁and ▁then ▁passes ▁through ▁the ▁Ch aut au qua ▁National ▁Wild life ▁Ref uge . ▁Ac ross ▁from ▁Hav ana , ▁the ▁Illinois ▁is ▁joined ▁by ▁the