Kōnan is located in the northern part of the Nōbi Plain, on the southern bank of the Kiso River.

Located approximately 20 km (12 mi) from the Nagoya metropolis, it is also a traffic node bordering Gifu Prefecture.

After the establishment of the modern municipalities system in the early Meiji period, the area was organized into villages within Niwa District, Aichi Prefecture.

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

In terms of national politics, the city is part of Aichi District 10 of the lower house of the Diet of Japan.