A little over five years ago (August 2011) I went on a trip to explore the last unpaved segment of Minnesota's state highway network: the section of MN-74 between Elba and US-61, which travels through the Whitewater Wildlife Management Area. So I thought I'd share, even though they're not the best quality.
Part one (https://imgur.com/a/KuvHo)
Part two (https://imgur.com/a/CdKWA)
Part three (https://imgur.com/a/Tn2Pu)
I got to drive this section this spring. Was probably not the best time to do so though as the wet, muddy road got to be a bit harrowing at points.
While this segment of MN 74 is the last remaining unpaved state highway segment, there are a few segments elsewhere that I can see MnDOT reverting back to gravel, if they're not turned back to begin with. The main one I'm thinking of is MN 65 north of MN 1. There just isn't the traffic volume there to cost-effectively justify a paved roadway, but there are a few others besides 65.