The province covers a total area of 5,000.83 square kilometres (1,930.83 sq mi) occupying the central and eastern section of Panay island in the Western Visayas region. If Iloilo City is included for geographical purposes, Iloilo has an area of 5,079.17 square kilometres (1,961.08 sq mi). The province is bordered by province of Antique to the west, Capiz to the north, the Jintotolo Channel to the northeast, the Visayan Sea and Guimaras Strait to the east, and the Iloilo Strait and Panay Gulf to the southwest.
The province is divided into two distinct geographic regions; the highlands of the Central Panay Mountain Range on the western border and the lowland plains which account for a larger portion of the province. Small islands east of its northernmost tip also dot the Visayan Sea – of these, Pan de Azucar and Sicogon are well-known. Mount Baloy is the highest mountain in Iloilo with an elevation of 6,261 feet (1,908 m) above sea level, located on the triple border of Iloilo, Capiz, and Antique. Other peaks are Mount Llorente 4,409 ft. (1,344m), Mount Sansanan 4,219 ft. (1,286m), Mount Napulak 4,095 ft. (1,248 m), Mount Balabag 3,728 ft. (1,136m).
Expansive fishponds and mangrove wetlands are found along the coasts and rivers of Oton, Iloilo City, Leganes, Zarraga, Dumangas, Barotac Nuevo, Anilao, Banate, Barotac Viejo, Ajuy, Balasan, and Carles.