Glenelg, a municipal town and watering place of Adelaide county, South Australia, on Holdfast Bay, 6½ m. by rail S.S.W. of the city of Adelaide. Pop. (1901) 3949. It is a popular summer resort, connected with Adelaide by two lines of railway. In the vicinity is the “Old Gum Tree” under which South Australia was proclaimed British territory by Governor Hindmarsh in 1836.