Sakai (堺市 Sakai-shi) is a city located in Osaka Prefecture, Japan on the edge of Osaka Bay at the mouth of the Yamato River. It has been one of the largest and most important seaports of Japan since the Medieval era. Following the February 2005 annexation of the town of Mihara (from Minamikawachi District), the city has grown further and is now the fourteenth most populous city in Japan, with 833,414 residents as of May 1, 2007. As of August 1, 2011, the city has an estimated population of 842,760 and a population density of 5,600 persons per km2. The total area is 149.99 km2.