Kagawa Prefecture is a prefecture of Japan located on the island of Shikoku. Kagawa Prefecture has a population of 949,358 and is the smallest prefecture by geographic area at 1,877 square kilometres (725 sq mi). Kagawa Prefecture borders Ehime Prefecture to the southwest and Tokushima Prefecture to the south.

Ehime Prefecture is a prefecture of Japan located on the island of Shikoku. Ehime Prefecture has a population of 1,334,841 and has a geographic area of 5,676 km2. Ehime Prefecture borders Kagawa Prefecture to the northeast, Tokushima Prefecture to the east, and Kōchi Prefecture to the southeast.