OP, unfortunately you are asking the question equivelent of "Where do you hunt ginseng?" Any place with a good yield is probably very protected by hunters. I found a site in a public field that I've been digging off and on for several years and I tell NO one where it is at. I've found silver and pre 1900s coins on it. You may find some general places in forums but the best thing to do is spend a day in the library studying the history of civil war camps and regiment movements in the area you want to hunt. Your luck may strike in finding a camp site that hasn't been dug. Also look for where schools once were and look around trees where kids climbed.