Sasebo is a core city located in the Nagasaki Prefecture of Japan. It serves as the second-largest city in the prefecture, following the capital city of Nagasaki.
As of April 1, 2024, Sasebo had an estimated population of 230,873 residents living in 102,670 households. The city covers a total area of 426.01 km² (164.48 sq mi) with a population density of approximately 540 persons per km².