Why was Toledo called Frogtown? Well, that's easier to explain than "holy Toledo". Practically the whole town was once a swamp. If you don't believe it, you should see the backyards in my, comparatively high ( That could be taken two ways. You should smell the neighborhood on a Saturday night. ), neighborhood.
Most of Northwest Ohio was part of the Great Black Swamp. There's a good introduction to the swamp , at Wikipedia. The Black Swamp Conservancy is working to preserve the few surviving patches, before they disappear under parking lots and housing developments.
The frog, in the picture, is a mosaic at the Lucas County Courthouse. It seems that, out of the thousands of courthouses in the US, Toledo's is the only one with a frog for a mascot.