Iloilo City the "Queen City of the South" first appears in the Maragtas legend of the ten Bornean datus who came to the island of Panay around the 11 or 12th century and bartered gold for the plains and valleys of the island from a local Ati chieftain. One datu, named Paiburong, was given the territory of Irong-Irong.

In 1566, as the Spanish conquest of the Philippines was underway and moving north toward Manila the Spaniards under Miguel Lopez de Legazpi came to Panay and established a settlement in Ogtong (now Oton , Iloilo). He appointed Gonzalo Ronquillo as deputy encomiendero, or governor.

In 1581 Ronquillo moved the town center approximately 12km west due to recurrent raids by Moro pirates, Dutch and English privateers, and renamed the area La Villa de Arevalo in honor of his hometown in Avila, Spain.

In 1700 due to ever-increasing raids the Spaniards again moved their seat of power some 25km westward to the village of Irong-Irong, which had a natural and strategic defense against raids and where, at the mouth of the river that snakes through Panay, built Fort San Pedro to better guard against the raids which were the only threat to the Spaniards' hold on the islands. Irong-Irong or Ilong-Ilong was shortened to ""Iloilo"" and with the natural port quickly became the capital of the province.

With the onset of the Spanish-American War, Spanish control of Iloilo ended in November 6, 1898 after a garrison of Spaniards of Negros ended in November 6, 1898 after the Americans defeated the Spanish in the Spanish-American War. Although long considered for centuries to be a city and major economic zone, the Philippine Senate, then under control as an American colony, was given chartered status on August 25, 1937. American forces liberated Iloilo from Japanese occupation March 25, 1945.

Iloilo is the provincial center of the region and is still one of the major argricultural centers of the Philippines, with the only UP campus with a college of agriculture and fisheries in Miagao, and the Aqua-culture Department of the South East Asian Fisheries Development Center (SEAFDEC) in Tigbauan, and home to Port San Pedro, one of five international trade ports in the Philippines. Iloilo is also the gateway to Boracay Beach, with a regional airport and the development of an international airport to open in 2006.