The North Dakota State Parks require a free permit to place a cache in a state park. The permit forms are available online. Information is available on the State Park's web site along with a list of caches in state parks and a map of caches. Link to the North Dakota State Parks Geocaching Page.
At this time, I have not been formally notified of any other policies in North Dakota. I have heard various rumors of policies involving other agencies, but do not know where those stand and have not been contacted by official representatives of those agencies.