ved ▁Rock ▁to ▁facil itate ▁the ▁fur ▁trade ▁and ▁defend ▁the ▁Illinois ▁against ▁the ▁I ro qu ois . ▁ ▁Later ▁the ▁fort ▁was ▁re located ▁to ▁the ▁present ▁site ▁of ▁Cre ve ▁Co eur , ▁near ▁Pe oria . ▁The ▁French ▁retained ▁a ▁presence ▁in ▁the ▁area , ▁with ▁small ▁trad ing ▁posts . ▁ ▁Prior ▁to ▁the ▁construction ▁of ▁the ▁Illinois ▁& ▁Michigan ▁Canal , ▁completed ▁in ▁ 1 8 4 5 , ▁Pe oria ▁was ▁the ▁only ▁large ▁settlement ▁on ▁the ▁River . ▁The ▁river ' s ▁trade ▁flow ed ▁down ▁to ▁be ▁domin ated ▁by ▁St . ▁Louis . ▁After ▁the ▁I & M ▁Canal ▁saw ▁a ▁string ▁of ▁cities , ▁such ▁as ▁La S alle , ▁Peru , ▁and ▁Ott awa ▁grow ▁along ▁the ▁river , ▁extending ▁Chicago ' s ▁influence ▁into ▁the ▁Mississippi ▁Valley . ▁During ▁the ▁nin ete enth ▁and ▁early ▁tw enti eth ▁centuries , ▁the ▁residents ▁of ▁the ▁river ▁towns ▁were ▁deeply ▁involved ▁in ▁har vest ing ▁the ▁river ' s ▁fish , ▁water f ow l , ▁muss els , ▁and ▁ice . ▁They ▁were ▁econom ically ▁and ▁cult ur ally ▁dependent ▁on ▁the ▁river , ▁building ▁up ▁indust ries ▁such ▁as ▁tour ism ▁related ▁to ▁du ck ▁hunting ▁and ▁sport ▁fish ing , ▁commercial ▁fish ing , ▁muss eling ▁for ▁the ▁button ▁fact ories , ▁and ▁ice ▁cutting ▁for ▁early ▁attempts ▁at ▁re fr iger ation ▁for ▁domestic ▁and ▁commercial ▁use . ▁ ▁With ▁the ▁construction ▁of ▁the ▁Chicago ▁San it ary