Ok I found the records on the 21st Wisconsin.
The regimental flag of the 21st Wisconsin was reported as "US Flag". With "Stone River" on the flag, 21st Wisconsin and the 21st Mississippi capturing it.
The National flag was "Number 43" on the War Department's returned colors. Listed as captured at Chickamauga, nothing follows.
Now Longstreet congratulated his men on captured flags. Some of their names I have.
Private W.H. Barnett, Company A, 21st Mississippi
Corporal R. Conrad, Company F, 21st Mississippi
Corporal J.F.M Skinner, Company G, 13th Mississippi
All that was listed (that I have found so far) for Humphrey's brigade.
Humphrey's reported 4-5 flags captured. The 21st Mississippi captured both flags of the 21st Wisconsin. I do not know as of yet to what flag the 13th Mississippi captured.
I wonder why there is only three soldiers mentioned if there were "4-5 flags" captured. Did one of those soldiers capturing more then one flag?
If anyone knows of a good Chickamauga book that has maps or shows Humphrey's Mississippi brigade in the ending actions would be a huge help.
The 21st Wisconsin was in "Starkweather's brigade" and fought early in the battle on the first day. Around 11:30am at Jay's Mill. (Page 142 "This Terrible Sound" by Peter Cozzens.)
Govan's brigade hit them on the flank. The 24th Illinois and 79th Pennsylvania were hit on the right flank and first. The 1st and 21st Wisconsin were on the left side of the formation and most likely did not lose a flag at this point. Nor was Humphrey's brigade anywhere near this point. The 4th Indiana battery of Starkweather's brigade was captured by Govan's left regiments. (6-7th Arkansas, 2-15th Arkansas and the 8th Arkansas).
I just need to see maps of Thomas's last stand, towards the end of the fight. If I can find the regimental locations of the Union line and Humphrey's line then whoever was on the 21st right or left must have lost a flag.
Have a good day,