Chillicothe, Ohio about 50 miles north of Serpent Mound is home to numerous earthen mounds. None are Adena Ceremonial mounds like Serpent Mound. The largest collection of mounds is found at Mound City; or what is formally called the Hopewell Culture National Historic Center, which is run by the National Parks Service. . The Hopewell Culture followed the Adena Culture.
There are over 23 mounds of varying shape and size on the grounds. They are Hopewell ceremonial mounds. Honestly, while they provide an incredible visual experience there is no sense of space, or feel to the space. It was most likely there long ago and has since dissipated since very few people visit and do ceremony, or pray there as we did. I must say that I did see one woman praying before one of the mounds--Excellent! I imagine that some are moved by the grandeur of the mounds which helps raise the consciousness of the space.
As I have been harping about for years sacred places need to be reinvigorated periodically through prayer/meditation/ceremony and good thoughts less their vibe and spiritual sense begins to diminish. See my Vortices and Spirals.
The other startlingly thing was that the earth energies that exuded from Serpent Mound are not present at Mound City. None of the mounds appear to have been placed on aspects of Mother Earth to tap into Her (energies, essences, consciousness...). I found no mounds that were even located over Ley Lines. Perhaps the focus of the mounds is was towards the sky, archeoastronomy.
Here are some pics from Mound City.