I created a map app where you can compare  hi-res USGS topo maps of the Choptank River watershed for different time frames, 1898-1944.

I did it by downloading KMZ files using the USGS TopoView app and publishing them on my own web server.  Then adding the URLs to my map app.  So easy, you can do it yourself.  Heh.  I’m sure you’ll want to read details here about the map scales, dates, and metadata.

To see all the layers for all the years, you have to view the larger map app.  No time?  Just zoom in with this map that shows only 1904-1918.  You’ll get the idea.  (Yeh, that a KMZ service can be slow.)

View larger map