I received a message from the Ohio Historical Society explaining how to see a map with all the markers for the state. If you know how to do it, the feature has been there all along.
1 – Go to the search site – http://www.ohiochannel.org/your_state/remarkable_ohio/search_markers_01.cfm
and click Submit without entering any search criteria. This will find all the markers in the state. Be patient, it takes about a minute to load them all.
2 – When the full list appears, click the Map Markers link at the top of the list. This will display the map shown above with over 1200 markers.
This is a regular Google map so you can pan and zoom.