The most fanciful is that Narrabeen is named after "narrow beans" which the English in the first year of settlement (1788) found and ate from a vine growing over beach sand.

Surgeon White indeed recorded getting ill from such beans but this was well north of Narrabeen, near Broken Bay.

According to The Budawa Aboriginal Signage Group Inc., Narrabeen means "source of fresh water".

The most popular theory involves Captain Henry Reynolds, a first fleeter who took his family to live near the Narrabeen Lagoon.

The location was then named after the young Aboriginal girl Narrabine/Narrabeen who tried to assist the victims and helped soldiers capture the killers.

[4] With the extension of the tram to Narrabeen in 1913 providing easier transport, the whole area around the lake became popular for holidays and camping.

In 1946 the Wakehurst Parkway was opened to North Narrabeen connecting the whole Pittwater area directly to Frenchs Forest and Seaforth.

The grassy parts of the beaches are situated on the endangered Themeda Grassland ecological community.

[10]) Most of the remnant ecological communities within the catchment have been defined as endangered ecological communities (EECs), e.g., Swamp Mahogany Forest is a component of Swamp Sclerophyll Forest, Coastal Freshwater Wetland a component of Freshwater Wetlands on Coastal Floodplains both declared as EECs, see the List of endangered ecological communities in NSW and Native Vegetation (2016).