The Passport to History is free at ND Tesoro gas stations and state historic sites.
Stop by a historic site, ND Tesoro gas station or a grocery store and pick up a free Passport to North Dakota History. This guide was put together by the State Historical Society of ND and has awesome info on state and national historic sites and parks. There's also details on Forest Service sites open to the public.
The Historical Society also unveiled a new "personal travel guide" program. It's called, History on Call, and it provides 24-hour access to streaming videos and narratives on your cell phone. Just call 701-557-9190 for this individual way to explore historic sites and attractions. Remember - many historic sites in the state are FREE to visit.
You can read the Passport online too, as well as find tons of other great ND historical information by visiting: http://history.nd.gov/.