 Four miles ( 6 @.@ 4 km ) west of Ogden , US 30 is joined by US 169 from the north . The two highways run concurrently until reaching Ogden , where the road becomes a four @-@ lane expressway . US 169 exits to the south at a partial cloverleaf interchange , while US 30 continues east through Boone County and descends into the Des Moines River valley . It ascends from the valley and travels another two miles ( 3 @.@ 2 km ) to a four @-@ way stop in Boone , which is the last stop along the route until Iowa 1 in Mt . Vernon . Three miles ( 4 @.@ 8 km ) east of Boone , it meets Iowa 17 at a diamond interchange . One mile ( 1 @.@ 6 km ) east of that interchange is a shortcut to northbound Iowa 17 . 
