The ruin of Cape St George lighthouse is perhaps the most significant European site in the park. The ruin was listed on the National Estate Register in 1981 in recognition of the ruin's important setting, stonework and as a relic of early European occupation.
During the 19th century, due to the number of shipwrecks occurring near Cape St George, it was decided that a lighthouse was vital for the safe navigation of coastal shipping. Unfortunately, due to insufficient research and consultation, the lighthouse was built in the wrong spot, and it came to be regarded as a navigational hazard.
In 1857, the colonial architect Alexander Dawson and an assistant surveyor E.F. Millington, investigated Cape St George for sites suitable for a lighthouse. Unfortunately Dawson's choice of sites was largely based on ease of construction, rather than the efficient function of a lighthouse. Without the input of any maritime expertise, the chairman of the Pilot Board authorised the first of Dawson's site options. Despite glaring deficiencies in the planning stage and disagreement by a majority of the board, the lighthouse was commissioned on 1st October, 1860. Thirty eight years and many arguments later, a replacement lighthouse would shine its beam from the northern side of Jervis Bay, at Point Perpendicular.
Even unlit, the lighthouse caused navigational problems especially on moonlit nights when the golden sandstone tower glowed in the dark. Near the turn of the century explosive charges were used to reduce the tower and parts of the keeper's quarters to rubble.
The people who lived at Cape St George Lighthouse were eerily prone to tragic events. In 1867 Isabella Jane Lee, the daughter of the principal lightkeeper from 1863-1873, died of typhus fever. In 1882, another resident, 13 year old George Gibson, died from pleurisy. Typhoid struck again in 1885 killing Florence Bailey, the 11 year old daughter of the third assistant lightkeeper. Her father, Edward Bailey, supplemented his income by fishing for sharks on the rocks below the lighthouse. In 1895, he was washed from the rocks. Entangled in his lines in heavy seas, he drowned and was taken by sharks as his son watched in horror.
Francis Henry Hammer, the son of Mary Hammer (a single woman who lived at the lighthouse) had a habit of pushing large rocks over the cliff edge to amuse himself. He either toppled over or lost his footing when part of the cliff collapsed. He was only nine or ten years old.
William Markham, the assistant lightkeeper from about 1878-1883, was kicked in the head by a horse and died before he reached Nowra Hospital.
One of the most disturbing tragedies involved two teenage girls. In 1887, Kate Gibson (the principal lightkeeper's daughter), tripped while skylarking with a loaded firearm. The gun discharged, striking her friend Harriet Parker (the assistant lightkeeper's daughter) in the back of the skull, killing her instantly. Her gravesite can be found in the Green Patch camping area.