Isahaya is a city located in the Nagasaki Prefecture of Japan. It serves as a regional center with an estimated population of 131,467 residents living across 55,169 households as of June 1, 2024.
The city covers a total area of 341.79 km² (131.97 sq mi), resulting in a population density of approximately 380 people per km². It is situated within the Nagasaki region and maintains its distinct identity as a municipality within the prefecture.