Collaroy Beach is also the landing point of the PPC-1 submarine cable, one of three backhaul communication links connecting Australia to the wider Internet.

[5] The name Collaroy is aboriginal for "big reeds",[6] and the suburb began its life as part of Narrabeen.

[13] The requirement for accurate maps in Australia led to the development of a control network of Trig stations.

Trig stations can be located on landmarks such as hills or high man-made structures such as buildings, or grain silos or water reservoirs.

The process of triangulation was used as the method to provide the locations of the trig stations, which were then used to connect to smaller scale surveys or for mapping.

The operators sat out in the open exposed to the elements and hand turned the aerial, even during tropical downpours, heavy winds, etcetera.

J S Whitelaw, Commander of Fixed Defences, spoke to P/O Swan requesting that the unit be moved adding the comment that 101RS would provide better air warning if it was relocated north of Sydney as Japanese ships were in the Coral Sea.

54RS at Collaroy was to become one of the more important radar sites particularly as a testing ground due to its relatively close proximity to the laboratory.

James Francis (Frank) Hurley (1885–1962), adventurer, photographer and film maker, was born on 15 October 1885 at Glebe, Sydney.

His book, Who Were They?, The Royal Australian Air Force on Collaroy Plateau in the Second World War,[20] is reputed to be one of the best written and researched unit histories available.

Warringah is home to over 900 native plant species, subspecies, varieties and forms that can be found from the coastal sand dunes and estuaries to sandstone ridge tops and plateaux.

It stands as one of the largest park cricket clubs on the Northern Beaches with around 25 junior and seniors teams.