Izu Province was a province of Japan in the area of Shizuoka Prefecture. Izu bordered on Sagami and Suruga Provinces. Its abbreviated form name was Zushū (豆州).

Shizuoka Prefecture is a prefecture of Japan located in the Chūbu region of Honshu. As of September 2023, Shizuoka Prefecture has a population of 3,555,818 and has a geographic area of 7,777.42 km2 (3,002.88 sq mi). Shizuoka Prefecture borders Kanagawa Prefecture to the east, Yamanashi Prefecture to the northeast, Nagano Prefecture to the north, and Aichi Prefecture to the west.