Knife River Indian Villages National Historic Site
Located just outside of the town of Stanton, about an hour and 20 minutes south of Minot, this unit of the National Park Service features exhibits and the remains of the Mandan, Hidatsa, and Arikara people who lived along the banks of the Knife River and were around when Lewis and Clark paid a visit in 1804. In fact the legendary Sakakawea, the Native American woman who accompanied Lewis and Clark on their trek to the Pacific, was from one of these villages.
The remains are nothing more than mounds on the plain approaching the banks of the Knife River, the site features a visitor's center with interpretive displays and a nice info film, plus a reconstructed earthlodge, the structures the Hidatsa and Mandan built to live in. Try to catch a ranger talk on the earthlodge...very interesting.
Plus it's definitely worth the drive through pretty country side which will be alive with the yellow of blooming canola and grey-blue of blooming flax if you come in late June/early July. And you can get a much coveted NPS passport stamp!
Take U.S. 83 south from Minot and then a right at State Highway 200A and watch for the signs to the historic site.