I did a study of those who were enlisted in Jefferson County during the War, thanks in part to your research, and found that a sizable part of 22 companies of Infantry and Cavalry and that single battery of artillery were organized in that county. Now I know that Pine Bluff was one of the ten recruitment post established by Governor Rector and that men from all over Southeast Arkansas came to Pine Bluff to enlist. But still that is a lot of men, I think totalling well over 2,000.
That would explain something that has always puzzled me about the folk history of Jefferson county. In 1861. '62, '63 Jefferson county seemed to be staunchly Southern. But by late 1863, '64' and on they are Unionist and the Confederate history of Jefferson County is almost lost. It appears that all the capable men did go off to war and Jefferson County was bled so dry that only old men boys and women were left. That most of those who left didn't come back because those who enlisted early were sent east of the Mississippi.
When the 5th Kansas Cavalry came into Pine Bluff Major Walker their commander was well known for his burning of southern sympathizers homes and anything that might give aid and comfort to southern families. He ran anyone of southern scentiment out of the County mostly to Texas. A lot of these people didn't return either.
This is one of the reasons why what happened at Camp White Sulphur Springs, and Fort Pleasent became such a "Black Hole" in the history of Arkansas and the war in Southeast Arkansas. Most of the people who were left in Jefferson County by the end of 1865 were those who had adapted to be able to live under a harsh Unionist occupation. And therefore Jefferson County is what it is today.
PS;
Because Donaldson McGregor was the Colonel of the 24th Ark Militia at Pine Bluff and became the Captain of Co. "D" "Clan McGregor" of Fagan's/Colquitt's 1st Arka. Inf. CS very early in May of 1861 with the secession of Arkansas, I am tending to believe that the original enlistees in that company were men of prior militia service. I believe that these men were drawn from both the "Jefferson Guards" and the "Southern Guards" of Jefferson County with possibly a few outside recruits and patriots thrown in to complete the company organization in such a short period of time.
We know that both of the "Jefferson Guards" and the "Southern Guards" became freestanding companies of their own in the 2nd AR. and the 15th AR. very early also, is the reason that I question whether the men of "Clan McGregor" where not possible origanized as militia prior to secession during the war fever period of February to May of 1861.
Remember that the adjuntant of "Clan McGregor" was a Lt. by the name of William Naylor Bronaugh, an instructor at the St John's College at Little Rock. This would seem to indicate to me that Colonel/Captain McGregor was organizing this company for a specific purpose after the Arsenal incident and for service to the Confederate states whether Arkansas secceded or not.