The stone medicine wheels of the Northern Plains are built from ordinary glacial erratic boulders, gathered rather than quarried and arranged by hand into a central cairn with spokes radiating outward, some, the Bighorn Medicine Wheel in Wyoming among them, arranged with an accuracy to solstice alignments that argues for careful, repeated observation over generations rather than a casual arrangement of rocks.
An active site, not an archaeological curiosity
Bighorn and comparable sites remain active ceremonial locations for specific Plains nations today, which sets them apart from an excavated ruin, and access is governed by negotiated agreements between the U.S. Forest Service and the tribes for whom the site remains sacred, including periods of restricted public access during ceremony. Leading ceremony at such a site is not open to any visitor with an interest, it belongs to recognized spiritual leaders within the specific nations whose practice it is.
A separate, unrelated use of the same name
This is worth separating clearly from the stone circles and labyrinths built by non-Native practitioners under the same borrowed name, structures with no connection to the Plains nations whose ceremonial sites these are, since conflating the two, an issue this atlas's companion article on the object already addresses directly, causes real harm to communities whose actual sacred sites are still in active, restricted ceremonial use.