It faces the Seto Inland Sea to the north and borders Tokushima Prefecture across the Sanuki Mountains to the south.

The city includes Awashima Island and Shishijima in the Seto Inland Sea between Shikoku and Honshu.

The area of Mitoyo was part of the ancient Sanuki Province and has been inhabited since prehistoric times.

Mitoyo has a mayor-council form of government with a directly elected mayor and a unicameral city council of 22 members.

In terms of national politics, the city is part of Kagawa 3rd district of the lower house of the Diet of Japan.

On the other hand, the Shonai Peninsula and offshore islands are focused on flower gardening and tourism.

Agriculture remains the largest industry, notably fruits such as grapes, mandarin oranges, and peaches.