Ishikari Subprefecture (石狩振興局, Ishikari-shinkō-kyoku) is a subprefecture of Hokkaido Prefecture, Japan, located in the western part of the island. The subprefecture covers 3,539.86 square kilometres (1,366.75 sq mi) and in 2011 had a population of 2,334,241. The subprefecture takes its name from the Ishikari River, the third longest in Japan, which flows through western Hokkaido and empties into the Sea of Japan in the city of Ishikari. There are 6 cities, three towns, and one village under its jurisdiction. Sapporo is both the capital of Hokkaido Prefecture and Ishikari Subprefecture.