Arkansas occupied a key position in the Confederate Trans-Mississippi Department. It offered a gateway for Confederate troops to move north and secure Missouri for the Confederacy, or for Union troops to move south towards Texas and Louisiana. During the war, Union and Confederate armies moved back and forth across the state engaging in numerous encounters. This paper is a year by year study of those encounters and engagements occurring in Arkansas between 1861 and 1865. Emphasis is necessarily placed on the significant campaigns and engagements. Actions which occurred in adjacent states but which militarily affected Arkansas are also discussed. The majority of the material was compiled from the Official Records.