Osaka is a designated city in the Kansai region of Honshu in Japan. It is the capital of and most populous city in Osaka Prefecture, and the second biggest prefectural city, third-most populous city proper in Japan, following the special wards of Tokyo and Yokohama. With an estimated population of 2.8 million as of October 1, 2025 and a population density of about 12,505 people per square kilometer, it is the largest component of the Keihanshin metropolitan area, the second-largest metropolitan area in Japan and the 10th-largest urban area in the world with more than 19 million inhabitants.