Botany Bay, inlet, New South Wales, SE Australia, just S of Sydney. It was visited in 1770 by James Cook, who proclaimed British sovereignty over the east coast of Australia. The site of the landing is marked by a monument on Inscription Point. The bay was named by Cook and Sir Joseph Banks because of the interesting flora on its shores. Although Australia's first penal colony was often called Botany Bay, its actual site was at Sydney on Port Jackson. The bay is now an important cargo port with chemical facilities and an oil refinery.