Panoramic views from Mount Cassel also known as Mount Didjun in the Grampians National Park, Victoria, Australia. Mount Cassel is part of the Mount William Range south-west of the picturesque village of Pomonal approximately 250 kilometres west of Melbourne. The summit of Mount Cassel is 736 metres above sea level and offers uninterrupted 360 degree views over Pomonal, the Black Range near Stawell, Lake Fyans, Lake Bellfield, the Wonderland Range and the Serra Range.