The oldest archaeological sites testify to the fact that Ilok was inhabited in the Neolithic Age, and there are numerous finds dating back to the Copper, Bronze and Iron Ages.

Rich finds of the Vinkovci and Vučedol cultures have been discovered. The Romans, after conquering this area, built a border fortress called Cuccium in order to protect the Danube-Pannonian route.

The name Ilok was first mentioned in 1267 as Wjlok, Wylhoc and Iwnlak. The most famous owner of Ilok was Nikola Iločki (1410 - 1477), a powerful Croatian-Hungarian nobleman and claimant to the throne, Viceroy of Croatia, Slavonia and Mačva, Duke of Transylvania and King of Bosnia. During his rule, Ilok experienced its golden age, and the town centre was fortified by walls that have remained partly preserved to this day. Nikola also had the Franciscan friary and the church of St John of Capistrano restored and rebuilt. St John of Capistrano, a European apostle and famous fighter against heresy and against the inroads of the Ottomans, died and was buried in Ilok. The town was granted the status of a free royal borough in the 15th century, and the official Town Charter was confirmed in 1525.

In the period 1526 to 1688, Ilok was ruled by the Turks. Valuable monuments of Islamic culture have been preserved. In the 17th century, the princely family Odescalchi became the new owners of the Ilok estate.

They restored Nikola’s old medieval castle, modernized the viticulture and built the town wine cellars beneath the castle, thus taking Ilok to its “second golden age”. In the 18th and 19th centuries, Ilok was the seat of the District Prefect of Srijem, the headquarters of the district, as well as the judicial, commercial and fair centre.

The history of Ilok can be revisited at the Museum of the Town of Ilok, which houses a rich archaeological, historical and ethnographic collection, as well as a collection of works of art.