Tom,
The 7th was racially diverse, but so far as I know they were Indians. I don't see a problem with anyone participating in any reenactment group that is willing to work at the craft. Learn how to drill, support your unit, etc. I can assure you that any of the units in my neck of the woods would welcome you. (8th T.V.I and 79th N.Y.). If you need help locating a unit in your area, try a local Civil War Round Table, Camp Chase Gazzette, Google search for Iron Brigade Units, etc.

My ancestor was in Co "K" of the 7th Wisconsin and I am looking for any information about that unit or him. Andrew Hamil Clark.

Curtis Miller