Valkó County (Hungarian: Valkó vármegye, Croatian: Vukovska županija, Serbian: Вуковска жупанија) was an administrative unit (county) of the medieval Kingdom of Hungary.[1] It was established in the 13th century, and included most territories of the present day Vukovar-Syrmia County, in modern Croatia, and western parts of the present day Syrmia District, in modern Serbia. The most important cities of the county were Vukovar and Ilok. Its territory was conquered by the Ottoman Turks in the first half of the 16th century.
The region was liberated during the Austro-Turkish War (1683-1699), but the county was not reestablished, since its territory was incorporated into the newly created Syrmia County.[2]
. Sima Ćirković. 2004. The Serbs. Malden. Blackwell Publishing. 9781405142915.
. John Van Antwerp Fine Jr.. The Early Medieval Balkans: A Critical Survey from the Sixth to the Late Twelfth Century. 1991. 1983. Ann Arbor, Michigan. University of Michigan Press. 0472081497.
. John Van Antwerp Fine Jr.. The Late Medieval Balkans: A Critical Survey from the Late Twelfth Century to the Ottoman Conquest. 1994. 1987. Ann Arbor, Michigan. University of Michigan Press. 0472082604.