In 1864, Union General Steele's Camden Expedition (March 23–May 2, 1864) was initiated to destroy all remaining Confederate forces to the east of the Mississippi and drive out all remaining Confederate sympathizers throughout Missouri and Arkansas and Mississippi. Due to Edwards now vast intelligence network and clandestine cache system of supplies, Shelby was able to lead a brilliant and determined harassment of the larger Union Army and in concert with other Confederate forces defeat the army and force it back into Little Rock where it was placed under siege after Shelby located and destroyed or captured the Army's entire supply trains at Mark's Mill.