Note to the State Historical Society of North Dakota: no one wants to see pictures of boxed archives on library shelves. Put up some real historical images, please. (Update...they did!)
Aside from that, though, there are some excellent, if somewhat scattered, North Dakota digital archives available here. Definitely worth exploring.
Best place to begin is Digital Horizons, a collection of images, documents, letters, maps, artifacts, a few audio files and so on, from a variety of state universities and historical collections. It's an ungainly, unfriendly CONTENTdm presentation, but what can you do...archivists seem to like that platform for some reason.
Browse by Subjects, including:
Next stop, especially for you family history types, is the ND Archives Databases, including:
A bit harder to find are an assortment of archive databases housed at ND State University:
A smattering of newspaper indexes are available:
Lastly, I'll note the North Dakota State University Digital Commons. While this is largely an academic collection of student theses, faculty papers, and the like, there is some historical content here as well, such as the Germans from Russia Heritage Collection.