Lady Julia Percy Island, known as Deen Maar or Dhinmar in the Gunditjmara language, lies 8.1 kilometres (5.0 mi) off the coast, in the Barwon South West region of Victoria, Australia in Bass Strait. The island is an unincorporated area under the direct administration of the Government of Victoria.

The Barwon South West is an economic rural region located in the southwestern part of Victoria, Australia. The Barwon South West region stretches from the tip of the Queenscliff Heads to the border of South Australia. It is home to Victoria’s largest provincial centre, Geelong and the major centres of Aireys Inlet, Apollo Bay, Camperdown, Colac, Hamilton, Lorne, Port Campbell, Port Fairy, Portland, Torquay and Warrnambool. It draws its name from the Barwon River and the geographic location of the region in the state of Victoria.