Cassilis is a ghost town in Gippsland, Victoria, Australia. It was named after a district and castle in Ayrshire, Scotland. In the late 19th century, at the peak of the gold boom, it was a thriving mining centre and home to more than 500 people. Gold-bearing quartz reefs were discovered in 1885 at Long Gully, and by 1889 there was a battery in operation as well as a general store, butchery, bakery and Mechanics' Institute hall.
A private school had already been operating when a government school commenced in the hall in 1890. The schools produced exceptional results, with pupils under headmaster McDonald gaining the highest percentage of scholarships in the State for several years. Two hotels, a coffee palace, hairdressers, bookmakers, two bank agencies and two post offices were also in existence. The first hydroelectric power station in Victoria was established at Victoria Falls to provide power and light for the mine.