The 1st/15th Arkansas was a field consolidation, one of several for the 15th Arkansas. Field consolidations were supposed to be temporary (although the 6th/7th Arkansas remained "temporarily" consolidated throughout the war). The 15th Arkansas was always an understrength regiment. Two of its companies refused to transfer to Confederate service in July 1861, and the regiment was sent east before it could recruit two new companies, so it went through the war with just eight companies. In addition, the regiment sustained heavy casualties and was unable to recruit enough men to make up for its losses. Therefore, the regiment was often field consolidated for tactical reasons with other understrength regiments -- the 13th Arkansas for a time, the 24th Arkansas, the 2nd Arkansas, the 1st Arkansas, etc. At the very end of the war, the 15th Arkansas was consolidated with the remnants of the other Arkansas regiments in its brigade, as the 1st Arkansas Consolidated Infantry.

In the field consolidations, the companies of the two regiments continued to muster separately and distinctly. There is reason to believe that temporary company designators were assigned for the duration of a specific campaign, for purely command and control reasons, but the individual companies always retained their identity on paper.

Be advised that the 15th Arkansas underwent several reorganizations, and changed its company designations at least three times.