The Macquarie Watchtower is the earliest known surviving, sandstone tower building in Australia, the oldest surviving building on Botany Bay, and has long been recognised as a picturesque landmark on the headland, particularly popular for wedding photographs. The c. 1820 Macquarie Watchtower is thought to have been commissioned by Governor Macquarie. Not only is it the oldest surviving watchtower in Australia but it is the only known tower specifically constructed for colonial border protection and the prevention of smuggling. Duperry makes reference to English soldiers stationed there when he visited in 1824.
It became the first Customs outstation in Australia in 1829 and operated as a Customs Station until 1903. It is also a rare surviving symbol of the vexatious issue of customs barriers between the colonies, which was one of the main factors underlying the push for Federation.