The Cooks River, a semi-mature tide-dominated drowned valley estuary, is a tributary of Botany Bay, located in south-western Sydney, New South Wales, Australia.

Botany Bay is an open oceanic embayment, located in Sydney, New South Wales, Australia, 13 km (8 mi) south of the Sydney central business district. Its source is the confluence of the Georges River at Taren Point and San Souci as well as the Cooks River at Kyeemagh, which flows 10 km (6 mi) to the east before meeting its mouth at the Tasman Sea, midpoint between the suburbs of La Perouse and Kurnell. The northern headland of the entrance to the bay from the Tasman Sea is Cape Banks and, on the southern side, the outer headland is Cape Solander and the inner headland is Sutherland Point.