Syrmia County was re-established in 1745. The county was included into the Kingdom of Slavonia, a Habsburg province, which was part of both, the Habsburg Kingdom of Croatia, and the Habsburg Kingdom of Hungary. The Kingdom of Slavonia was mainly inhabited by Serbs and Croats. In 1848 and 1849, the area of the county was part of the Serbian Voivodship, a Serbianautonomous region proclaimed at the May Assembly in Karlovci. Between 1849 and 1860 the area was part of the Voivodeship of Serbia and Banat of Temeschwar, a separate crown land of the Austrian Empire. During this time the county did not existed since voivodeship was divided into districts. After 1860, Syrmia County was established again, and was incorporated into the Kingdom of Slavonia, which was a completely separate Habsburg province at the time. In 1867, as a consequence of the Ausgleich between the Austrians and the Hungarians, Kingdom of Slavonia was incorporated into Transleithania, the half of Austria-Hungary run from Budapest, and in the Hungarian-Croatian Settlement of 1868, it was incorporated into Croatia-Slavonia, a formally separate kingdom within the Kingdom of Hungary, which had a certain level of autonomy and was ruled by its own ban. After World War I, the area of Syrmia County became part of the newly formed Kingdom of Serbs, Croats and Slovenes in 1918 and this was confirmed by the Treaty of Saint-Germain in September 1919. The County of Syrmia was an official administrative division of the Kingdom of Serbs, Croats and Slovenes between 1918 and 1922, and then was transformed into the Province of Syrmia.
Demographics
According to the census of 1870, the county had 120,352 inhabitants.
According to the census of 1890, the county had 347,022 inhabitants.
In 1900, the county had a population of 381,739 people and was composed of the following linguistic communities: Total:
Serbian: 168,982
Croatian: 100,360
German: 67,027
Hungarian: 23,539
Slovak: 11,415
Ruthenian: 4,345
Romanian: 601
Other or unknown: 5,470
According to the census of 1900, the county was composed of the following religious communities: Total:
Eastern Orthodox: 172,818
Roman Catholic: 171,142
Lutheran: 22,473
Calvinist: 5,750
Greek Catholic: 4,681
Jewish: 3,894
Unitarian: 2
Other or unknown: 979
In 1910, the county had a population of 414,234 people and was composed of the following linguistic communities: Total:
Serbian: 183,109
Croatian: 106,198
German: 68,086
Hungarian: 29,522
Slovak: 13,841
Ruthenian: 4,642
Romanian: 587
Other or unknown: 8,249
According to the census of 1910, the county was composed of the following religious communities: Total: