Glenrock Lagoon, an intermediate fresh water small coastal creek,[1] is located within the Lake Macquarie local government area in the Newcastle and Hunter regions of New South Wales, Australia.

The lake is located near the Newcastle suburbs of Adamstown and Dudley and is situated about 153 kilometres (95 mi) north of Sydney.

Drawing its catchment from Flaggy Creek within the Glenrock State Recreation Area and the Awabakal Nature Reserve, the small lagoon is quite shallow with an average depth of 2.4 metres (7 ft 10 in).

[citation needed] Glenrock Lagoon came into existence 6,000 years ago when the sea level stabilised after the last ice age.

Archaeological evidence has been found to date a campsite at Swansea Heads, some miles to the south of Glenrock, at 7,800 years (Dept of Lands 1990).

However, the news did not get back to Sydney and it was Lieut John Shortland R. N. who received credit for the discovery of coal in Newcastle on 9 September 1797.

Even today, coal can still be found in the cliff face on the northern headland at the mouth of Glenrock Lagoon.

[8] In a letter dated 12 October 1842, to W. Kirchner of Sydney, Friedrich Wilhelm Ludwig Leichhardt describes a walk through the valley on his way from Newcastle to Redhead via Charlestown.

Floods, that have swept down with irresistible power during the heavy winter rains, have uprooted big trees, and have produced the wildest conflagration of closely entangled life and death.