Usu (有珠郡, Usu-gun) is a district located in Iburi Subprefecture, Hokkaido, Japan. As of March, 2008, the district has an estimated Population of 3,009 and a density of 14.7 persons/km2. The total area is 205.04 km2.
April 1, 1919 - Due to the Sōbetsu, Hokkaido 2nd class municipal status enforcement, the village of Tokushunbetsu was formed within Usu District. (3 villages)
June 1920 - Parts of the village of Tokushunbetsu merged into the village of Kimobetsu, Abuta District (now the town of Kimobetsu).
August 1, 1925 - The village of Date became the 1st class town of Date. (1 town, 2 villages)
April 1, 1939 - The village of Sōbetsu became the 1st class village.
June 1, 1943 - 1st and 2nd class municipal status abolished. The village of Tokushunbetu became an officially designated village, according to the Ministry of Interior.
October 5, 1946 - Designated municipal status enforcement abolished.
September 1, 1950 - The village of Tokushunbetsu was renamed Ōtaki.
January 1, 1962 - The village of Sōbetsu gained town status to become the town of Sōbetsu. (2 towns, 1 village)
April 1, 1972 - The town of Date gained city status to become the city of Date. (1 town, 1 village)
March 1, 2006 - The village of Ōtaki merged into the city of Date.[1] (1 town)
