You're exactly right, Anthony. All of the "Trans-Mississippi Rifle Regiments" provided opportunities for confusion with Arkansas regiments serving in the Army of Tennessee. A good example is the number of "4th Arkansas" men captured at Pleasant Hill, Louisiana. Of course, the 4th Arkansas was east of the Mississippi and not engaged in the Red River Campaign; however, the 32nd Arkansas fought in that campaign, and was briefly known as the 4th Trans-Mississippi Rifle Regiment -- when captured, the men identified themselves as belonging to the "4th Arkansas", and set future researchers up with an extra hoop to jump through.