Facing the Tokyo Bay coast, the inland mountainous area is part of the Bōsō Hill Range.

Chiba Prefecture Kyonan has a humid subtropical climate (Köppen Cfa) characterized by warm summers and cool winters with light to no snowfall.

Kyonan has a mayor-council form of government with a directly elected mayor and a unicameral town council of 12 members.

In terms of national politics, the city is part of Chiba 12th district of the lower house of the Diet of Japan.

Kyonan serves as a commercial center for the surrounding region of southwest-central Chiba Prefecture.

Mount Saga has been used for narcissus cultivation at least from the Edo period 1603–1868, and Kyonan remains one of the largest producers of the flower in Japan.