Iwami Province

 was an old province of Japan in the area that is today the western part of Shimane Prefecture. It was sometimes called . Iwami bordered Aki, Bingo, Izumo, Nagato, and Suō provinces.
In the Heian period (794–1192) the capital was at modern-day Hamada. 
In the Kamakura period (1192–1333) the Masuda clan belonged to the Minamoto clan (Genji) and conquered Iwami Province.
History.
During the Muromachi and Sengoku periods, the battles were very furious in this area.
At first, the Masuda clan was in alliance with the Ōuchi clan in neighboring Suō, but later the Masuda clan belonged to the Mōri clan in neighboring Aki.
Maps of Japan and Iwami Province were reformed in the 1870s when the prefecture system was introduced. At the same time, the province continued to exist for some purposes. For example, Iwami is explicitly recognized in treaties in 1894 (a) between Japan and the United States and (b) between Japan and the United Kingdom.