Looking into The Great Mound at Mounds State Park in Anderson, Indiana. Photo by Mike Luoma.

Ancient Astronomical Earthworks of the American Midwest

Celestial Alignments and Embanked Enclosures in Indiana’s Mounds State Park

Mike Luoma
5 min readOct 15, 2021


What little we know about the Adena and Hopewell indigenous cultures of the pre-contact North American Midwest we have gleaned from what remains of their many mounds and earthworks. There is still much to be learned. The earthworks have not usually been valued, however, by post-contact settlers, and so what remains is a tiny fraction of what was once built.

Entrance to Mounds State Park, Anderson, Indiana. Photo by Mike Luoma.

The unassuming earthworks of Mounds State Park in Anderson, Indiana, demonstrate enormous complexity — there is much more to them than first meets the eye. They are some of the best, most intact examples left of these earthworks in east central Indiana. 300 Mounds were once counted in the vicinity. Fewer than a hundred are said to be left in some shape or another — but the two major earthworks here comprise half of those actually intact. Great Mound is said to be one of the best preserved of all of the earthworks in the entire Ohio Valley region.

Archeoastronomy shows these embanked enclosures align with risings and settings of the sun and moon on solstices and equinoxes, and with the movement of the planets, more than 100 of the brightest stars, and star groups like the Pleiades, as well.

Looking into the interior of the embankment towards the center island of the Great Mound, Mounds State Park, Anderson, Indiana. Photo by Mike Luoma.

This doesn’t actually mean these Native Americans were akin to what we know today as astronomers. Rather, the celestial world was a part of their world. Participating with the patterns of celestial objects may have been seen as honoring them, acknowledging them, and their patterns. And incorporating those celestial objects and patterns into rituals may have tied those rituals into those greater patterns of the universe.

The Anderson Great Mound is a relatively large circular embankment and ditch with a central island. The earthwork is almost 350 feet across, about as long as a football field, and nearly a quarter-mile in…



Mike Luoma

Author, Podcaster, Radio Host & Music Director, Explorer, Researcher, Science Fiction & Comic Book Creator. From Vermont.