Cincinnati Tri-State Kentucky Travel Boone County Arboretum – Union, KY By: Been There with Kids Looking for a free day of fun in northern Kentucky? I suggest the Boone County Arboretum. The kids had a blast learning about the different plants …. Share this:Click to share on Facebook (Opens in new window)Click to share on Twitter (Opens in new window)Click to share on Pinterest (Opens in new window)