Their website says "The largest online newspaper archive", while I haven't had to stray too far around the planet to find newspaper articles I must recommend subscribing to this on-line newspaper archive. As of today, I have found 500+ articles concerning my ancestors!
The University of Calgary Libraries and Cultural Resources website holds is an amazing collection from across Canada which I imagine is growing constantly. Right now their collection from Saskatchewan contains 360+ books!!
They are creating a digital archive of the history of North Dakota. A staggering amount of work and one for which I am grateful. My ancestors spent limited time in North Dakota but I found much information in this rich resource!
Don't forget the humble newspaper as a source of family history! In my early days of the hunt I spent many hundreds of hours at the library scrolling through microfilm of old newspapers. It is tedious but if you have some dates of weddings, births and deaths you might get lucky reading through newspapers!