Hamamasu (浜益郡; -gun) is a district of Ishikari Subprefecture, Hokkaido, Japan.
In 2004 the district had an estimated population of 2,179 and a density of 7.00 persons per km². The total area is 311.16 km². As of September, 2004, Ishikari City, Hamamasu Village and Atsuta Village of Atsuta District are considering merging. This would dissolve Atsuta and Hamamasu Districts.
Towns and villages
