 Now in Iowa County , I @-@ 80 continues towards the eastern end of the 50 @-@ mile ( 80 km ) stretch of straight highway . It turns slightly to the southeast near the Ladora exit and straightens again at the Marengo interchange , where <unk> Manufacturing , a farm implement manufacturer , advertises its business to passing travelers by arranging farm implements into sculptures . A few miles east , in Williamsburg , is the northern end of Iowa 149 . The Williamsburg exit is the location of a Tanger Outlet Mall . The next interchange marks the southern end of US 151 . Both the Iowa 149 and US 151 interchanges serve the Amana Colonies which are located 10 miles ( 16 km ) to the north . 
