I thought I’d throw this up here as I think it’s an awesome tool that many Wisconsin counties offer. I’m not exactly sure if every county has one but I believe that they may. Try googliing your county name with “GIS” or “web mapping”.
Here are links to Jackson and Trempeleau co’s. Jackson’s is awesome and has some great features along with current color aerial photo’s.
http://www.tremplocounty.com/landrecords/disclaimer.htm
http://www.jacksoncountymapping.com
you can use these for finding public ground, measuring land area’s, finding corner sections(and their description) among a whole host of other things. Hopefully someone will find this useful.