One reason for the decline in population in some Arkansas counties was due to migration. A lot -- and I mean a LOT -- of Arkansans left the state during and after the war. A great many of them went to Texas, some went further west. Arkansas was absolutely devastated by the war -- socially and economically -- and Reconstruction just added to the misery. So a lot of folks just pulled up stakes and headed west.

Regarding the 1870 census, I took a close look at that census for several Arkansas counties a few years back, and just shook my head in disbelief at the number of households headed by widows. What a tragedy.