Gero is a city located in Gifu, Japan. As of 31 October 2017, the city had an estimated population of 33,283, and a population density of 39 persons per km2, in 12,253 households. The total area of the city was 851.21 square kilometres (328.65 sq mi). The city is famous for its hot springs.

Gifu Prefecture is a prefecture of Japan located in the Chūbu region of Honshu. Gifu Prefecture has a population of 1,991,390 and has a geographic area of 10,621 square kilometres (4,101 sq mi). Gifu Prefecture borders Toyama Prefecture to the north; Ishikawa Prefecture to the northwest, Fukui Prefecture and Shiga Prefecture to the west, Mie Prefecture to the southwest, Aichi Prefecture to the south, and Nagano Prefecture to the east.