Thanks for your efforts. Here's part of Captain McMath's diary which was found by a Federal soldier on a battlefield after his death, June 30, 1862:

We remained in camp near the Lewis House until the 10th of August when we moved our camp to this place about 6 miles from our old camp 1-3/4 miles from the railroad near Bristoe on the road from the Junction to Richmond. We remained at this place until the 26th inst. During the time we were in camp at this place we had a great deal of rain. We were encamped on a very low ground & had a very unpleasant time. During our stay there our men suffered severely with measles while there in consequence of so much rain & the ground being so low & damp. We lost two of our men while there of Typhoid fever Andrew J. Ellet died August 21st & John Gibson on the 25th day of August of the same disease. We placed head boards at the head of their graves with their names, date of their death & company & Regt. they belonged to. We move[d] our camp to this place about ¾ mile east of our old camp towards Bristoe. James Ray died of Typhoid fever after a protracted spell of about four weeks he first took the measles & was fast recovering when he acted imprudently in leaving his tent and having a bath set which resulted in his death on Wednesday evening September 11th 1861. Eli W. Goree died Sept. 12/61 of Typhoid fever after an illness of about 30 days was first took with measles had a back set and got up. With prudence would have got well. Robert C. Carroll died Sept. 15th 1861 in camp near Bristoe of pneumonia after an illness of about 10 days. Left our camp near Bristoe for Centreville Sept. 21/61 arrived at said place same day about 3 PM left in Bristoe in hospital 39 of our men. Came to Centreville with fifty rank & file. Thomas Rigsby died in camp near Bristoe Sept. 27th 1861 of Typhoid fever after an illness of about 35 days. Thomas Daley died in camp near the Same place chronnick diareah Sept 30th 1861.

Hopefully McMath's directions will help identify the camp of the 11th Alabama. The camp near Bristoe was also called Broad Run in some accounts. Col. Moore of the 11th Alabama addressed the medical director at Bristoe Station several weeks later, requesting that all members of his command who were improving be forwarded to his camp, and all those really sick be sent to hospitals in Richmond.