Map of Japanese provinces (1868) with Aki Province highlighted
Aki Province (安芸国 Aki no kuni) or Geishū (芸州) was an old province in the area of Hiroshima Prefecture on the island of Honshū.
Itsukushima in Aki Province, woodblock print by Hiroshige
In the Meiji period, the provinces of Japan were converted into prefectures. The maps of Japan and Aki Province were reformed in the 1870s.
Itsukushima jinja was the chief Shinto shrine (ichinomiya) of Aki. 
Media related to Aki Province at Wikimedia Commons