Hioki is located in the central part of Kagoshima Prefecture, in the mid-west of the Satsuma Peninsula.

The western part of the city faces the East China Sea, and is home to Fukiagehama Beach, one of Japan's three largest sand dunes.

Hioki is part of ancient Satsuma Province and was one of the centers of the Shimazu clan during the Kamakura and Muromachi periods.

Hioki has a mayor-council form of government with a directly elected mayor and a unicameral city council of 20 members.

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