When did the mound builders live in Ohio?

The two most famous mound builders that lived in Ohio were the Hopewell and Adena people. Archaeologists have uncovered artifacts from other prehistoric peoples; the Paleo, Archaic, Glacial Kame, and Fort Ancient, but, they were not located in large mounds of earthen structures like those of the Hopewell and Adena. 

The Adena people came to Ohio around 1000 B.C. The Adena's were located around river valleys near the Chillicothe area of Ohio. They built cone-shaped mounds. The Serpent Mound is thought to be Adena because of its closeness to other Adena mounds, although nothing has been found in this mound to tell archaeologist for sure.  

The Hopewell people came to Ohio around 200 B.C. and disappeared around 600 A.D. Their mounds were shaped like circles, squares, and rectangles. They lived near river valleys as well. "It is thought that the Adena were absorbed by the Hopewell " (Lutz). This would account for the similarities between the two cultures. What the Adena people made and built, the Hopewell did it a little better.