Trig Stations around Sydney

Trig stations (or Trigonometric Stations) were critical to surveyors in providing reference points across Australia as they mapped the country. Thousands of trig points were generally sited on the highest and most prominent point in the local area, which means they often provide a great view – although many are now surrounded by trees and bushes. The trig stations or trig points typically consist of a black disc on top of four metal legs or a concrete pillar, while older ones consist of a rock cairn supporting a post and vane.

About a third of trig stations are located on government land; the map and list below are focused on those in and adjacent to national parks and nature reserves. This is very much a “work in progress”: having recently discovered the prevalance of these mostly hidden sites, I’ll add more trig points as I find time to reach them! If I’ve missed any in a national park or you’ve got a favourite, please leave me a comment at the bottom!

• Trigs in Sydney’s north (see also Ku-ring-gai Chase National Park trigs and Garigal National Park)  
• Trigs in Sydney’s south (including Royal & Heathcote National Parks)
• Trigs of the Central Coast (including Bouddi, Dharug, Popran and Yengo National Parks)
• Trigs of Newcastle and the Hunter Valley 
• South Coast trigs (south of the Illawarra)

MAP KEY
Blue - a trig station referenced from SIX Maps
Green - trig stations I've visited and documented - see below
Orange / Red - trig station difficult to reach / located on private land and not publicly accessible

The Best Trig Stations around Sydney

Many trig stations lie abandoned in thick scrub, offering no views despite being on the top of a hill. Others are located just off a walking track, and provide a magnificent and unexpected view for little effort. The trigs below are some of my favourites, which are worth making the effort to visit.

GARIGAL NATIONAL PARK

	TS10447 CROMER HEIGHTS (157m) An easy clamber up some rocks to the trig point rewards with sweeping views over the bushland and to the ocean in the distance. Distance: 3km return. Ease of Access: Easy/Moderate Location: 33°43’50.7″S 151°15’19.9″E. How to get there: Informal track off Red Hill Main Trail More info: Red Hill Loop
	TS3329 NARRABEEN (135m) While just the metal column remains of this trig station, it’s just off a wide service trail, and give you a great view over Narrabeen Lake and the ocean to the east. Distance: 2.2km return. Ease of Access: Easy Location: 33°42’35.0″S 151°15’51.4″E. How to get there: Follow the Slippery Dip Trail from Deep Creek Reserve More info: Deep Creek Loop

KU-RING-GAI CHASE NP

	TS638 ARDEN (191m) This is one of the more challenging ones to get to, but in return you get sweeping views over West Head and out to Pittwater and the Barrenjoey Peninsula. Distance: 3.8km return. Ease of Access: Moderate/Hard (no track) Location: 33°38’02.9″S 151°15’03.4″E. How to get there: Bush-bash up a ridge from the Waratah Trail More info: Rediscovering the Waratah Trail
	TS7220 BARRENJOEY (104m) The trig point is located on the site of one the original Barrenjoey Head lightstations. It’s a short scramble up from the main Access Trail up to Barrenjoey Head. Distance: 2.2km return. Ease of Access: Easy/Moderate Location: S33° 34.758′ E151° 19.716′. How to get there: Short bush-bash up from the main trail More info: Barrenjoey Lighthouse bushwalk
	TS2005 EURO (169m) A relatively easy off-track walk from the Basin Trail. The trig station mast is easy to spot above the trees, and there are great views in all directions. A few Aboriginal engraving sites are nearby. Distance: 3.2km return. Ease of Access: Moderate Location: 33°35’59.8″S 151°17’17.4″E. How to get there: Bush-bash from Basin Trail (West Head) More info: Secrets of the Basin Track
	TS5929 TABER (204m) An easy walk up from Cottage Point Road via a walking trail to the trig station, which has been damaged by bushfire – you need to continue 100m beyond the trig for a great view over Coal and Candle Creek. Distance: 0.4km return. Ease of Access: Easy Location: 33°37’51.3″S 151°12’28.2″E. How to get there: Follow Ausgrid access trail off Cottage Point Road More info: Trig Bagging at Cottage Point
	TS4625 WARATAH (182m) Nice views over Coal and Candle Creek from this solidly-constructed trig station, which is accessed via a unmarked bushwalking track off the Waratah Trail Distance: 7km return. Ease of Access: Moderate Location: 33°37’46.0″S 151°13’48.5″E. How to get there: Follow Waratah Track; look for unmarked bushwalking track on the left More info: More info: Rediscovering the Waratah Trail
	TS2779 WILLUNGA (233m) Willunga Trig is the highest point in Ku-ring-gai Chase National Park, and offers great views toward Pittwater and as far as the city of Sydney to the south. Distance: 1.5km return. Ease of Access: Easy Location: 33°37’46.0″S 151°13’48.5″E. How to get there: Take the Willunga Trail from West Head Road More info: Willunga Trail bushwalk

MUOGAMARRA NATURE RESERVE

TS2871 LLOYD (210m) Muogamarra is only open a few weekends each year: the short walk to the trig point is one of the ones worth doing.Ciews over the Hawkesbury River and toward West Head and Barrenjoey. Distance: 2.8km return. Ease of Access: Easy (firetrail) Location: 33°32’48.1″S 151°11’27.4″E. How to get there: Follow Lloyd Trig Firetrail More info: Lloyd Trig bushwalk

BRISBANE WATER NATIONAL PARK

TS5606 WONDABYNE (251m) Outstanding 360-degree views from this trig point on top of Mount Wondabyne toward Woy Woy and the surrounding central coast suburbs to the east, and Brisbane Water National Park and Wondabyne station to the west. Distance: 7.4km return from Woy Woy Road Ease of Access: Easy How to get there: Multiple bushwalking tracks from Woy Woy Road or Wondabyne Station More info: Pindar Caves and Mt Wondabyne bushwalk

More Information

A Brief History of Trig Stations in NSW

The first or baseline trig station was established at Lake George in 1867 (TS778 Lake George) by the Trigonometrical Survey of New South Wales. The surveying efforts continued for almost fifty years until it was suspended to reduce cost at the outset of WWI, with about a third of NSW covered. The survey was resumed intermittently between the two World Wars predominantly by the Royal Australian Survey Corps, and by 1966 the geodetic network covered about half of the state. In 1973 a plan was formulated to revise and complete the network, starting in the SydneyNewcastle-Wollongong region and continuing along the coast and then westwards. Many old-style cairn and pole stations were replaced by a concrete pillar with demountable mast and vane. Eventually, over 6,000 traditional ‘passive’ trigonometrical (trig) stations were installed, now managed by NSW Land Registry Services.

The relevance of the traditional trig stations was significantly reduced by the introduction in 2009 of the Global Navigation Satellite System (GNSS) Continuously Operating Reference Station (CORS) networks, or CORSnet-NSW. Covering all of NSW, CORSnet-NSW provides centimetre-level real-time positioning and allows nearby equipment and machinery to accurately determine coordinates for positioning and guidance solutions.

However, while it took only five years to cover more than two thirds of NSW with 150 active CORSnet-NSW trig stations by July 2014, passive control stations are still necessary. Consequently, the Land and Property Information (renamed the NSW Land Registry Services in 2017) initiated a process to select a subset of trig stations to maintain. Multiple criteria (including prominence within the survey network, ease of access, historical significance and monument quality) are used to assess each trig station across NSW and calculate a ‘TrigStar’ score out of 100 and a corresponding rating out of 5 stars. Based on this rating, the top 500-700 (about 10% of the total) will be maintained.

Read more: Preservation and Upgrade of Trigonometrical Stations in NSW [PDF]

Trig Station status

Some trig stations have a letter after the trig station code – this provides additional information on the trig station or survey mark:

Code	Status	Description
D	Destroyed	Evidence was found that the mark is destroyed
F	Found	Mark was found in good condition
N	Not Found	Mark was searched for, not found, but no evidence exists to indicate that it was destroyed
R	Restricted	Mark is in a restricted area and requires special permission for occupation.
S	Subsidence Area	Mark is located in an area identified as being subject to movement
U	Uncertain	Mark was found, however it was in an unstable condition or there was evidence that it had been disturbed or moved.

Resources

There’s a surprising amount of detail on most of the trig stations, with their locations and inspection reports publicly available:

• SIX Maps provide access to a range of NSW primary spatial data – check the “Survey Marks” box to view trig stations (TS) as well as State Survey marks (SS) and Permanent Marks (PM)
• Survey Mark Sketches show the physical position of numbered Survey Control Marks (enter the number only, not the TS prefix to download a report)
• Guide to the History Trigonometric Stations of Sydney’s North by Tony Dawson is the definitive guide to trigs in this area – but it can be hard to find a copy of the book. 
• Geocaching Australia has thousands of trig stations registered as “virtual caches”, with additional information and useful access comments in the logs. There are also maps available, such as this one of all Australia trig station geocaches.