Having grown up in North Dakota. The far eastern part of the state is super flat because it used to be the bed of the glacial Lake Agassiz.
![](https://live.staticflickr.com/3300/3657179139_495039d543_c.jpg" width="800" height="600" alt="North Dakota is flat")
Credit to
https://flickr.com/photos/mbietz/
Then about 1/3 of the way from the Eastern border of the state you hit the Missouri plateau which is where rivers in the area stop flowing north and start flowing south (mostly). (sorry, spent 30 minutes trying to resize this image)
![](https://www.ndstudies.gov/gr4/sites/default/files/unit4/fig36a.jpg)
Credit to
https://www.ndstudies.gov/gr4/geolog...s-north-dakota
At that point it gets more hilly and there is the Missouri river area. Once you get past the Missouri you will start to see buttes and by the time you get to the western border you get to the Bad Lands of North Dakota (Theodore Roosevelt National Park)
![](https://render.fineartamerica.com/images/rendered/share/19034741)
Credit to
https://fineartamerica.com/featured/...n-brueske.html