John:
Chapman's History of Edgefield County, published about 1895, is probably your best bet, but it is full of errors. You need to get the reprint edition; the original edition did not have an index. My interest is the Hamtpon legion, and there were three Stevens who had a connection to Comapny B of the Legion Infantry. Others were in the 14 S.C., 19 S.C., and I suspect the 7th S.C., as well as militia units. Sadly, there i almost nothing of those. The records just didn't survive. Send me the names of interest and I will check them out in my copy of Chapman.

One other great resource is the Old Edgefield District Genealogical Society in Edgefield, the largest society in S.C. Contact Tonya Browder at OEDGS@aikenelectric.net. If you are close enough, you really shoudl visit their excellent library; got lots of neat data.
Lee