Kamagaya is a city located in Chiba Prefecture, Japan. As of 1 December 2020, the city had an estimated population of 109,941 living in 50,485 households and a population density of 5200 persons per km2. The total area of the city is 21.08 km2 (8.14 sq mi).

Shimofusa Air Base , officially Shimohusa Air Base, is a military aerodrome of the Japan Maritime Self-Defense Force. It is located 5.4 NM east of Matsudo in Chiba Prefecture, Japan. The base straddles the border between Kashiwa and Kamagaya cities.