Usuki is a city situated on the east coast of the Ōita Prefecture in Japan. The municipality covers a total area of 868.02 km² (335.14 sq mi) and maintains a population density of approximately 120 persons per km².
The city is notably recognized for its historical and cultural assets, specifically the Usuki Stone Buddhas, which are designated as a National Treasure. Additionally, the region is known for its production of soy sauce.