In general, has anyone found system maps that show neighborhood primary voltages? For example, if I am looking for the primary voltage in a Cincinnati industrial neighborhood, in a general sense only, would Duke Power publish that online? Thanks.

I would be very surprised if they did. Back in my utility days, my group kept these types of maps updated but they were not for public use. I checked the PUCO (Public Utilities Commission of Ohio) website and they have nothing that I could find.

If you are really interested you could call the utility but not sure what their response might be. They could claim that it is considered a critical energy infrastructure and would be exempt from disclosure to the public.

Another would be look a the size of the pole insulators and look at a Hubble catalog. Most utility distribution is 4.16, 12.47, 13.2, 13.8, 34.5kV. I probably missed some voltages there.

The "insulator method" is actually a great option. We had one exception however where a 23 kV line had 69 kV insulators because we were someday going to convert the line to 69 kV.

Very rare exception so yes, the "windshield tour with binoculars" is a great way to go.