Dee Why is a suburb of northern Sydney, in the
state of New South Wales, Australia 18
kilometres north-east of the Sydney central
business district. Dee Why is the administrative
centre of the local government area of
Warringah Council, and along with Brookvale is
considered to be the main centre of the
Northern Beaches region.

Dee Why is contained in the drainage basin of
Dee Why Lagoon, and stretches from Victor
Road in the west to Dee Why Beach in the east,
and from the crest of Wingala Hill to the
northern edge of Dee Why Lagoon.

Dee Why Beach runs for about 1.2 km along the
eastern border, overlooking the Tasman Sea. To
the north are the dunes separating the beach
from the Dee Why Lagoon. At its southern end
is the Ted Jackson Reserve

Behind the beach's remaining dunes, to the
north of The Strand, is Dee Why Lagoon. Its
entrance marks the northern end of Dee Why
Beach and the southern extent of Long Reef
Beach.