Osaka, the capital city of the Osaka Prefecture, is located in the Kinki region in Japan's Honshu Island. AsiaRooms.com is here offering you all the information regarding Osaka Population. Up to the year 2005, the estimated population of Osaka was 2,640,097, while its density was 11,894 persons per sq. kilometers. This is about 7% of the total population Japan, and it ranks second to that of the Tokyo Prefecture. The people of Osaka speak a dialect that belongs to the standard Japanese.