Sado Province

 was a province of Japan until 1871; since then, it has been a part of Niigata Prefecture. It was sometimes called or . It lies on the eponymous Sado Island, off the coast of Niigata Prefecture (or in the past, Echigo Province).
Sado was famous for the silver and gold mined on the island. In the Kamakura Period, the province was granted to the Honma clan from Honshū, and they continued to dominate Sado until 1589, when Uesugi Kagekatsu of Echigo Province took over the island. The Tokugawa shōguns later made Sado a personal fief after Sekigahara, and assumed direct control of its mines.
Since 2004 Sado city has comprised the entire island.