Looking for information on duties of Regimental and Brigade Headquarters Guards

My Greatx2grandfather was in the 22nd NYVI and was detached to guard the Regimental HQ for two months and then the Brigade HQ for all but the last few weeks of the unit enlistment (two year regiment). I am wondering what the duties of such a Guard would have been, where he would have served during battles, and how he might have earned or been detailed to that duty. Also any pointers to photos or histories of the 1st corps, 3d division, 3d brigade would be of interest. Thanks.

Oh man this is so exciting I mean. It must be for you knowing your GGF has served in the civil war I am digging into it right now and hope to come up with some answers to your questions

i would bet hq duty was better than serving on the front lines-guarding the commander of a regt or brigade got you better food i can guess, many probably became couriers.in abattle they could used as reinforcements.i was curious to know what they did also so i thought id post a responce to get the question out there again.

Well have found a book about the 22nd NYVI that includes letters from a pvt detached to Brigade HQ, his duties day to day was foraging, getting it from HQ or otherwise with four other soldiers.

But during combat his story sounds like he is on the line with or very near his regiment, with the horrors and dangers associated therewith (he wouldnt even talk about Antietam in detail due to pen not being uup to the task and Fredericksburg mentions the balls shot at pickets over head and laying low in regimental position etc).

So not real clear yet what they did. Still more of book to read though.