Ilok is the easternmost town in Croatia forming a geographic salient surrounded by Vojvodina. Located in the Syrmia region, it lies on the Fruška Gora hill overlooking the Danube river, which forms the border with the Bačka region of Serbia. The town is home to a Franciscan monastery and Ilok Castle, which is a popular day trip for domestic and cross-border tourists.

Syrmia is a region of the southern Pannonian Plain, which lies between the Danube and Sava rivers. It is divided between Serbia and Croatia. Most of the region is flat, with the exception of the low Fruška gora mountain stretching along the Danube in its northern part.