Miyakonoj is a city located in Miyazaki Prefecture, Japan. The city was founded on April 1, 1924. On January 1, 2006 the towns of Takaj, Takazaki, Yamada and Yamanokuchi merged into the city. As of 2008, the city has an estimated population of 169,384 and a population density of 259 per Square kilometer. It covers an area of 653.31 Square kilometers making it the largest city in the prefecture. Miyakonoj is experiencing a declining population, which may be due to migration to Tokyo, Osaka and other major cities. Several other cities in Miyazaki are also facing this problem. On January 1, 2006, the towns of Takaj, Takazaki, Yamada and Yamanokuchi, all from Kitamorokata District, were merged into Miyakonoj to form a larger urban area.