Map of Japanese provinces (1868
) with Tsushima Province highlighted
Tsushima Province (対馬国 Tsushima-no kuni) was an Japanese island province off the west coast of the island of Kyushu. It was sometimes called Taishū (対州) .
The province was the Tsushima Islands, which is today part of Nagasaki Prefecture.
The capital city of the province was located at Izuhara.
View of Tsushima Province, woodblock print by Hiroshige
In the Meiji period, the provinces of Japan were converted into prefectures. Maps of Japan and Tsushima Province were reformed in the 1870s.
Kaijin jinja was the chief Shinto shrine (ichinomiya) of Tsushima. 
Media related to Tsushima Province at Wikimedia Commons