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 lies Solo River. Its metropolitan area, consisting of Surakarta City and the surrounding six regencies, was home to 6,837,753 inhabitants according to the official estimates for mid 2023, 526,870 of whom reside in the city proper.