Arthur is a rural municipality in the province of Manitoba in Western Canada. It is located in the southwestern part of the province, along its border with the state of North Dakota in the United States. The 2006 Census showed a population of 440 persons, a decline from its 2001 population of 480. The administratively separate town of Melita is surrounded by its territory.
According to Statistics Canada, the rural municipality has an area of 765.77 km² (295.67 sq mi). The administratively separate town of Melita is enclaved by the Rural Municipality of Arthur, at a little north of its centre.