From August 10 to November 3, 1863 Davidson commanded the 1st Division of Frederick Steele's Army of Arkansas in his most distinguished role in the west. He led Union advance into central Arkansas and won the Battle of Bayou Fourche, which led directly to the fall of Confederate-held Little Rock. After the Little Rock expedition, Davidson commanded the cavalry in the Dept. of the Gulf before returning to command the cavalry in the Dist. of Southeast Missouri.