Hornby Lighthouse, Navigation lighthouse at South Head, Sydney Harbour National Park, Australia

Hornby Lighthouse is an octagonal sandstone tower of four levels on South Head, with a basement store cut 10 feet into solid rock. Its topmost level has a cantilevered iron and timber catwalk, and the metal pitched roof is topped by an observation fleche. The shaft has simple stepping, string courses and small oval and square windows.

A signal station had operated near the site since 1790. After the Dunbar wreck in August 1857 (121 lives lost) and the Catherine Adamson two months later (21 lives), a committee recommended a 9.1-metre light. The tower was finished in 1858, opened by Governor Sir William Denison and named after his wife Caroline's family, the Hornbys.

The light was named after Caroline, wife of Governor Sir William Denison and daughter of Admiral Sir Phipps Hornby, who opened the tower in 1858. Locals long called it the "Lower Light", distinguishing it from Macquarie Lighthouse, the "Upper Light". Its signal station site has guided shipping since 1790.

The lighthouse and keeper's cottages sit at the tip of South Head, reached on foot through Sydney Harbour National Park; the station was transferred to the NSW National Parks & Wildlife Service after 1975. The headland is exposed, so bring a jacket against wind and wear shoes with grip for uneven tracks. The light itself is automated and not open for climbing.

The keeper's cottages are not Georgian; they were built in the 1840s and 1860s, with two rooms added to each in 1877. Cottage One, a two-bedroom dwelling, has a 1795 cannon in its yard and was long used to house NSW Maritime Services personnel.