Vinkovci served as a temporary de facto seat of the county during the Croatian War of Independence with some institutions still remaining in the town as of 2020.

In historically relevant languages the county is known as German: Gespanschaft Vukovar-Syrmien, Latin: Cornacensis-Sirmiensis, Hebrew: מחוז ווקובאר-סריימיה and Church Slavonic: Вльковарьскосрємьскꙑ жоупаниѩ.

Some of the villages in the region were settled by Salonica front Serbian soldiers and families as a reward for their contribution to war efforts.

The old Habsburg Syrmia County remained a subdivision of the Kingdom of Serbs, Croats and Slovenes (Yugoslavia from 1929) until 1922; it then became an oblast (with the same borders) until 1929.

The puppet state and Nazi forces conducted criminal policy of Holocaust, Genocide of Serbs in the Independent State of Croatia and Romani genocide by destruction of Vinkovci Synagogue, devastation of Vukovar Synagogue, Dudik Killings, Ivanci massacre and other crimes in the region.

For a long period during the existence of the Socialist Republic of Croatia the area of the modern day county was organized in three municipalities of Vinkovci, Vukovar and Županja.

Before the Croatian War of Independence the Baroque town was a prosperous, mixed community of Croats, Serbs and other ethnic groups.

In 1990, an armed insurrection was started by Croatian Serb militias, supported by the Serbian government and paramilitary groups, who seized control of Serb-populated areas of Croatia.

Despite the battle the events in Eastern Slavonia developed slower than in Krajina and were under much stronger and more direct influence from the central government in Belgrade.

[4] They however led to the establishment of self-proclaimed SAO Eastern Slavonia, Baranja and Western Syrmia which subsequently joined the as well self-declared Republic of Serbian Krajina.

Complete military defeat of Krajina during the Operation Storm and perception that similar or more devastating fate may follow up in Eastern Slavonia increased willingness to compromise and commitment on all sides to pursue peaceful resolution of the conflict.

As the result of the War Vukovar became known in majority Croat community as the Hero City and is today a common emotional patriotic or nationalist reference commemorated officially as a Remembrance Day public holiday on November 18.

Vukovar-Srijem County lies in the far northeastern part of Croatia, in the regions of eastern Slavonia and west Syrmia.

Census data on Roma in Croatia may not always be reliable due to stigma associated with free expression of ethnic identity in this community.

Area of modern-day Vukovar-Srijem County experienced number of spontaneous or state organized voluntary and involuntary waves of violent and peaceful emigration, immigration and politically motivated population persecution.

Members of the same ethnic group in addition to social class may often distinguish themselves according to the time spent in the region (autochthonous or new and relatively new communities) and place of origin.

After the Operation Flash Serbian refugees from western Slavonia settled in the region yet majority of them together with some of the locals emigrated during and after the reintegration process.

After the 2013 enlargement of the European Union all communities in the county were affected by significantly increased levels of emigration to Western Europe (Germany, Ireland, Austria, United Kingdom).

Serbs form majority population in municipalities of Negoslavci (97.19%), Markušica (90.10%) (Gaboš, Karadžićevo, Ostrovo, Podrinje), Trpinja (89.75%) (Bobota, Bršadin, Pačetin, Vera, Ludvinci) and Borovo (89.73%).

[10] Ethnic Serb independent politician Dragan Crnogorac's list got 2,394 ballots (3.49%), which is below the 5% required to be assigned any seats in the Assembly.