Muallim District is being administered by the Land and District Office Muallim that located in Slim River, Perak. The current District Officer of Muallim is Encik Mohamad Fitri bin Hassan.
The east and west parts of the Ulu Bernam mukim is separated by the town of Hulu Bernam, which is a part of Hulu Selangor, Selangor. West Ulu Bernam was an exclave of the district and the mukim.