I'm not sure if anyone else has provided these links, so if they have, please excuse the duplication

The University of Minnesota at Crookston's Digital archives contains the 1916, centennial and bicentennial histories of Polk County, MN. These are in pdf format, and available for viewing for free at the following links:

http://blog.lib.umn.edu/jamcarls/myblog/2011/11/
http://blog.lib.umn.edu/jamcarls/myblog/2012/05/

Happy sluething!