Surakarta, known colloquially as Solo, is a major city in Central Java, Indonesia. The 46.72 km2 (18.04 sq mi) city adjoins Karanganyar Regency and Boyolali Regency to the north, Karanganyar Regency and Sukoharjo Regency to the east and west, and Sukoharjo Regency to the south. On the eastern side of Solo flows Solo River. Its metropolitan area, consisting of Surakarta City and the surrounding six regencies, was home to 6,899,402 inhabitants according to the official estimates for mid 2025, 529,079 of whom resided in the city proper.