ISTRIA, a peninsula of Italy, in the territory of Venice, situated in the northern part of the Adriatic Sea. It is bounded by Carniola on the north; and on the south, east, and west, by the sea. It produces wine, oil, and pastures; and there are quarries of fine marble. One part of it belongs to the Venetians, and the other to the house of Austria. Capo d'Istria is the capital town.