"Indian Mounds" is a misnomer as they were built centuries before Native Americans crossed over the Bering land bridge. A lot of mystery still exists about who the "Mound Builders" actually were and what became of them.
They built hundreds of mounds along rivers in the south, in TN and AL, GA and up into Ohio and Michigan.
I borrowed a book on the subject from the library written about 1925 by a UM Professor who had counted the mounds in MI. While there were a lot in Wayne and Macomb counties in our area, there was only one found in Oakland County.
Most in Wayne had been dug out by "pot hunters" in the 18th/19th century.