 Prior to gaining separate representation, areas now under the jurisdiction of Agusan del Sur were represented under the Department of Mindanao and Sulu (1917–1935) and Agusan Province (1935–1969).Republic Act No.4979, approved in a plebiscite held simultaneously with the 1967 elections, split the old Agusan Province into Agusan del Norte and Agusan del Sur and provided them each with a congressional representative.