▁Minnesota ' s ▁border ▁with ▁Iowa . ▁The ▁Root ▁River ▁dra ins ▁the ▁county , ▁flow ing ▁east ward . ▁The ▁North ▁Branch ▁and ▁the ▁Middle ▁Branch ▁combine ▁east ▁of ▁Sh ady ▁Creek , ▁while ▁the ▁South ▁Branch ▁meets ▁their ▁combined ▁flow ▁at ▁Pr eston . ▁Bear ▁Creek ▁dra ins ▁the ▁lower ▁part ▁of ▁the ▁county , ▁dis charg ing ▁into ▁the ▁Root ▁in ▁the ▁eastern ▁part ▁of ▁the ▁county . ▁Will ow ▁Creek ▁also ▁dra ins ▁a ▁portion ▁of ▁the ▁lower ▁county , ▁dis charg ing ▁into ▁the ▁Root ▁at ▁Pr eston . ▁The ▁Upper ▁Iowa ▁River ▁flows ▁east ward , ▁mostly ▁in ▁ad jo ining ▁Iowa ▁count ies , ▁but ▁briefly ▁enters ▁F ill more ▁County ▁near ▁the ▁mid point ▁of ▁its ▁southern ▁border . ▁ ▁The ▁county ' s ▁terrain ▁consists ▁of ▁rolling ▁hills , ▁car ved ▁by ▁g ul lies ▁and ▁d rain ages , ▁with ▁the ▁available ▁area ▁dedicated ▁to ▁agricult ure . ▁The ▁terrain ▁s lop es ▁to ▁the ▁east ; ▁its ▁highest ▁point ▁is ▁on ▁the ▁lower ▁western ▁border , ▁at ▁ 1 , 3 7 8 ' ▁( 4 2 0 m ) ▁AS L . ▁The ▁county ▁has ▁a ▁total ▁area ▁of ▁, ▁of ▁which ▁ ▁is ▁land ▁and ▁ ▁( 0 . 0 9 %) ▁is ▁water . ▁ ▁The ▁county ▁is ▁part ▁of ▁the ▁Dr ift less ▁Area ▁or ▁Pale oz o ic ▁plate au . ▁This ▁part ▁of ▁Minnesota ▁was ▁ice - free ▁during ▁the ▁last ▁ice ▁age . ▁F ill