abraham lincoln american civil war arkansas arkansas river arkansas in the american civil war army of the mississippi army of the tennessee battle of bayou fourche battle of cane hill battle of chalk bluff battle of chickasaw bayou battle of cotton plant battle of helena battle of old river lake battle of pea ridge battle of pine bluff battle of poison spring battle of prairie grove battle of saint charles confederate states army frederick steele gunboat ironclad warship mississippi river president of the united states texas union army united states vicksburg campaign