Rumoi (留萌郡; -gun) is a district located in Rumoi Subprefecture, Hokkaido, Japan.
As of 2004, the district has an estimated population of 4,337 and a density of 6.91 persons per km². The total area is 627.29 km².
Town
In July of 2004, the city of Rumoi, the town of Obira, and the town of Mashike in Mashike District formed the South Rumoi Three-Municipality Merger Board, aiming at merging the three, in which case Rumoi and Masahike Districts would cease to exist.
