The Mississippi 3rd Infantry Battalion (Hardcastle's) was expanded into the 45th MS Infantry following the battle of Shiloh and then -- due to significant loss in numbers -- reduced again following the battle of Kennesaw to the 3rd Battalion MS Infantry (Hardcastle's).The Mississippi 45th Infantry Regiment was formed from Hardcastle's Battalion. The regiment seems to have been also called the Thirty-third. The State Register of Commissions shows H. Charlton commissioned Lieutenant-Colonel and T. A. Jones Major of the Forty-fifth, to date from April 20, 1862.Company A -- Duncan Riflemen (raised in Simpson County, MS)Company B -- Insurgents (raised in Itawamba County, MS)Company C -- Raymond Minute Men (raised in Hinds County, MS)Company D -- Choctaw Rough & Ready Company (raised in Choctaw County, MS)Company E -- McNair Rifles, aka Pike County Rifles (raised in Pike County, MS)Company F -- Tippah Highlanders (raised in Tippah County, MS)Company G -- Mississippi Volunteers (raised in Pontotoc County, MS)Company H -- Capt. Roberts' Company [27th AL Infantry] (raised in AL)Company I -- Capt. Wright's Company [27th AL Infantry] (raised in AL)Company K -- Capt. Charlton's Independent Company (raised in Hinds County, MS)