Cape Don Lighthouse Complex, constructed 1915-20, is significant as an intact group of buildings and structures which represent the process and function necessary for marine navigation. It is significant as the first major project undertaken by the Commonwealth Government after it assumed functional responsibility for coastal lighting in 1915 (Criterion A.4). The light tower, completed in 1917, is of structural/technical interest as an early example of a reinforced concrete tower, and one of the few pre World War Two lighthouses constructed using concrete. Most were of a block house form. Concrete towers only became more common after 1950 (Criteria B.2 and F.1). The residences are significant for illustrating an architectural style that succeeds in providing climatically comfortable accommodation in an otherwise remote and inhospitable location (Criterion D.2).
The construction of the Cape Don light was the first major project undertaken by the Commonwealth Government after it assumed functional responsibility for coastal lighting in 1915.
Due to cyclones the lighthouse was built over three eight month work seasons which extended from April to November each year. Materials shipped from Darwin were landed 5km east of the construction site and then transported over land on horse drawn flat bed trucks.
The light was first exhibited on 15 September 1917.
The original optical apparatus consisted of a third order 500mm focal radius revolving lens on a mercury float rotating pedestal driven by a clockwork mechanism.
A 55mm vaporised kerosene incandescent mantle provided the light source.
The illuminant was subsequently changed to a 120 volt tungsten halogen lamp powered by diesel generators.
In June 1983 the light was converted to automatic operation.
The original optical apparatus, replaced by a parabolic reflector array and gearless pedestal, has been retained for possible future use.
The 36m tower is a grey reinforced concrete cylindrical column with a splayed base.
It is surmounted by a 10ft 9in lantern manufactured by Chance Bros of Birmingham, England.
The optical apparatus comprises an array of four vertical panels, each panel consisting of four 300mm diameter rear surfaced parabolic reflectors fitted with low power (12 volt 36 watt) quartz halogen lamps.
The lamps are electrically connected in pairs with beams 180 degrees apart.
The array is mounted on a gearless rotating pedestal revolving at three rotations per minute.
The apparatus gives a character of flashing every ten seconds with an intensity of 2,60 000 candela giving a nominal visible range of 22 nautical miles. Accommodation facilities comprise of three large houses. The houses are constructed from concrete block work and are set on high blocks with reinforced concrete beams. They have timber floors which extend out to wide verandahs.
Large pivoting storm screens enable the verandahs to be enclosed in times of inclement weather. Internal walls are high with screened vents located towards the ceiling.
Double doors, with screens provide access from the five main rooms to the verandah.
The doors have two long and narrow halves containing twelve small panes of glass each.
A breezeway divides the rooms into sections. One side contains three rooms and the other two larger rooms with a corridor between them leading from the central breezeway to the verandah.
The houses have been altered to the extent that the original breezeway between the main house and service wing has been enclosed as a living area.
Corrugated galvanised iron is used as roofing, this has been replaced by corrugated asbestos cement roofing in one of the houses.
Small storage sheds, also in concrete block work, are adjacent to each of the houses. Additional worksheds in block work exist around the base of the light.
Some galvanised iron sheds also exist within the complex.
The sheds contain a powerhouse, maintenance workshop and store.
A bore and mill is located on the northern boundary and a raised water tank is situated in the precinct's centre. An abandoned garden lies next to the bore and mill.
An abandoned tramway extends east from the complex to Christies Bay. It is a narrow gauge facility with light steel rails affixed to locally cut sleepers.
The tramway is only partially intact and in places, particularly towards the causeway, has been almost totally removed. However, pieces of rail and sleepers indicate its original path which has been used as a vehicular access track. A causeway, approximately 90m x 4m, has been constructed from rocks and locally extracted aggregate through a mangrove swamp into Christie's Bay. At its end is a small CGI shelter in which goods might have been stored prior to being transported to the lighthouse sight. Extending out into the bay is a series of upright tramway rails. These would have supported decking for jetty facilities. Luggers were used to transport materials from Darwin to Cape Don during the site's construction and/or a supply line prior to the introduction of larger vessels which use a different inlet.