[1] Iloilo first elected its representatives at-large in the 1943 Philippine legislative election for a seat in the National Assembly of the Second Philippine Republic, with a separate district created for Iloilo City being a chartered city since 1936.
[2][3] Before 1943, the province which also included Guimaras was represented in the national legislatures through its first, second, third, fourth and fifth districts.
[1] The province was also earlier represented in the Malolos Congress of the First Philippine Republic in 1898 by appointed delegates residing in Luzon.
[4] The five districts were restored in Iloilo ahead of the 1941 Philippine House of Representatives elections whose elected representatives only began to serve following the dissolution of the Second Republic and the restoration of the Philippine Commonwealth in 1945.
An at-large district would not be used in the province again until the 1984 Philippine parliamentary election for five seats in the Batasang Pambansa which it shared with its highly urbanized capital city.