In addition to the ND places mentioned by CloudDriver, add Fort Union which is an old restored trading post near the confluence of the Yellowstone River where it joins the Missouri, and add a visit to Mandan on the Missouri River just west of Bismarck where Lewis & Clark spent the winter of 1804-05 while on their westward journey. North Dakota is a great state to visit, the highways are in excellent condition too! I'm a native South Dakotan and prefer to travel in ND over SD whenever making a trip eastward......and it's not so overloaded with tourists either.
