Istria County (ˈɪstriə; Istarska županija; Regione istriana, "Istrian Region") is the westernmost county of Croatia which includes the biggest part of the Istrian peninsula ( out of , or 89%).
Administrative centers in the county are Pazin, Pula and Poreč. Istria County has the largest Italian-speaking population in Croatia.
The caves near Pula (in latinium Pietas Julia), Lim fjord, Šandalja, and Roumald's cave, house Stone Age archaeological remains. Less ancient Stone Age sites, from the period between 6000 and 2000 BC can also be found in the area. More than 400 locations are classified as Bronze Age (1800–1000 BC) items. Numerous findings including weapons, tools, and jewelry) which are from the earlier iron era around the beginning of common era.
The Istrian peninsula was known to Romans as the terra magica. Its name is derived from the Histri, an Illyrian tribe who as accounted by the geographer Strabo lived in the region. Romans described them as pirates who were hard to conquer due to the difficulty of navigating the territory. After two military campaigns, Roman legions finally subdued them in 177 BC.
With the fall of the Western Roman Empire in 476, Istria was conquered by the Goths and then by the Byzantines. During Byzantine rule, it was shortly ruled by Avars. Istria was annexed by the Lombards in 751, by the Avars in 774, by the Franks during the reign of Charlemagne in 789, and successively controlled by various dukes, (Carinthia, Merano, Bavaria). Later it was run by the patriarchs of Aquileia.
In 1267 the Republic of Venice annexed the western and southern coast of the Istrian peninsula because of the strong presence of the autochthonous Italian community; during this period the region prospered. The major Istrian cities were reborn under Italian government; it was in this half millennium that they developed architecturally and culturally. The eastern half of Istria was administered by the Habsburgs, and was referred to as "Imperial Istria" with its capital at Pisino (German: Mitterburg).