OB Flat

OB Flat is a south-eastern suburb of Mount Gambier in South Australia.

The name for this suburb is believed to derive from a herd of cattle bearing the brand "OB" (owned by O. Beswick) which once roamed in the area.

OB Flat is located within the federal division of Barker, the state electoral district of Mount Gambier and the local government areas of the District Council of Grant and the City of Mount Gambier. It is also part of Mount Gambier’s urban sprawl.