Maybe I do not know how to use this map. What does all the black allover the state of Ohio represent?
I'm assuming you are viewing the entire state and have the "Wells" box checked on the right side. In that case, you're seeing every well on file with ODNR in the state, and at that scale, all of the little well markers are blending together to form huge black areas. Zoom in on a smaller area and the individual wells will be more apparent.