These histories are free online. I’ll continue to update the list. There are other regimental histories that are modern and under copyright- those are not included. Feel free to contact me with any that are missing.
Georgia: Chatham Artillery, Cobb’s Legion Cavalry, 30th, 42nd
Louisiana: Washington Artillery, 3rd
Maryland: The Maryland Line (1st Artillery, 2nd Artillery- Baltimore Light, 3rd Artillery, 4th Artillery- Chesapeake, 1st Cavalry, 1st Cavalry Company K, 2nd Cavalry, 1st MD, 2nd MD, 21st Company B), History and Roster of MD Volunteers (many units)