ans ▁the ▁Missouri ▁River ▁between ▁Ro ose vel t ▁and ▁Rich land ▁Count ies ▁in ▁Mont ana , ▁USA , ▁between ▁B ain ville ▁and ▁Fair view , ▁Mont ana , ▁and ▁near ▁Fort ▁Union ▁Tr ading ▁Post ▁National ▁Historic ▁Site ▁and ▁the ▁g host ▁town ▁of ▁Mond ak ▁near ▁Mont ana ' s ▁eastern ▁border ▁with ▁North ▁Dak ota . ▁Snow den ▁Bridge ▁is ▁a ▁near ▁tw in ▁of ▁the ▁Fair view ▁Bridge , ▁which ▁cross es ▁the ▁Y ellow stone ▁River ▁in ▁North ▁Dak ota , ▁both ▁brid ges ▁having ▁been ▁built ▁by ▁Mont ana ▁Eastern ▁Railway ▁within ▁ten ▁miles ▁of ▁each ▁other ▁over ▁different ▁rivers ▁in ▁different ▁states . ▁ ▁The ▁designer , ▁John ▁Alexander ▁Low ▁W add ell ▁( 1 8 5 4 – 1 9 3 8 ), ▁based ▁the ▁Snow den ▁Bridge ▁on ▁the ▁South ▁Hal sted ▁Street ▁Bridge ▁( 1 8 9 3 ) ▁in ▁Chicago . ▁ ▁When ▁completed , ▁Snow den ▁Bridge ▁was ▁the ▁longest ▁( 1 , 1 5 9 ▁feet ) ▁vertical - l ift ▁bridge ▁in ▁the ▁world . ▁ ▁Its ▁cost ▁was ▁$ 4 6 5 , 3 6 7 , ▁equivalent ▁to ▁at ▁least ▁$ 1 0 , 0 0 0 , 0 0 0 ▁at ▁the ▁beginning ▁of ▁the ▁ 2 1 st ▁century . ▁ ▁The ▁War ▁Department ▁required ▁a ▁mov able ▁span ▁on ▁the ▁grounds ▁that ▁large ▁steam bo ats ▁might ▁vent ure ▁up ▁the ▁Missouri ▁during ▁the ▁month ▁or ▁so ▁that ▁the ▁river ▁was ▁navig