Hornby Lighthouse, Sydney

Hornby Lighthouse is a heritage-listed active lighthouse located on the tip of South Head, New South Wales, Australia, a headland to the north of the suburb Watsons Bay. It marks the southern entrance to Port Jackson and Sydney Harbour, as well as lighting the South Reef, a ledge of submerged rocks. It is the third oldest lighthouse in New South Wales. Designed by Mortimer Lewis and listed on the (now defunct) Register of the National Estate.

The site of the first navigational beacon in Australia providing warning to mariners. A dominant Sydney landmark which appears to have been in continuous use since the 1840s as a controlling point for shipping entering and leaving Port Jackson.

A solid sandstone tower with connected watch keepers quarters built in the early 1840s and designed by the Colonial Architect Mortimer Lewis. The tower is octagonal in plan having four levels and a basement store cut 10 feet into a solid rock. The topmost level has a cantilevered iron and timber catwalk and the metal pitched roof is surmounted by an observation fleche. Decoration is minimal but the form of the shaft with simple stepping, string courses and small panel oval and square windows is typical of restrained Colonial Georgian building work. The wing for staff quarters in an "I" plan with enclosed verandahs either side.

This building probably c. 1850s building having very good ashlar work to external walls with each elevation recessed within a frame of foundation, eaves and quoin mouldings. Windows are marked by simple classical sill and lintel mouldings. The hipped roofs originally of slate are now sheeted in asbestos cement. A good timber picket fence encloses the property which is in good condition and well maintained.

The lighthouse is a tapered circular structure, built of curved dressed sandstone and standing 9.1 metres (30 ft) above the ground. It is painted with distinctive red and white vertical stripes. The sandstone was quarried locally.

On top of the tower is a non-ferrous metal balcony and railing, painted white, surrounded the glass-enclosed lamp.

To the west of the tower are the two Georgian style sandstone cottages, now painted, constructed from the same locally queried sandstone, and having timber verandahs and picket fences. The original slate roofing has been replaced with corrugated asbestos.