Map of Japanese provinces (1868) with Tosa Province highlighted
Tosa Province (土佐国 Tosa no kuni) was an old province of Japan in the area of Kōchi Prefecture on the island of Shikoku. It was sometimes called Doshū (土州) .
The province had borders with Iyo and Awa Provinces.
The ancient capital city of the province was near modern Nankoku.
In the Meiji period, the provinces of Japan were converted into prefectures. The maps of Japan and Tosa Province were reformed in the 1870s.
Tosa faced the Pacific Ocean.
Tosa jinja was the chief Shinto shrine (ichinomiya) of Tosa. 
Media related to Tosa Province at Wikimedia Commons