Like almost all Southern states during the American Civil War, Arkansas provided a number of units to fight for the Union organized from African-Americans and Northern sympathizers. Despite having the third smallest white population of any Confederate state, Arkansas supplied more troops for the Union army than any other Confederate state except Tennessee. A total of 5,526 African-Americans served in Union units raised from the State of Arkansas.
References
List of Arkansas Civil War Union units Wikipedia(Text) CC BY-SA