The creek flows from Petersham, past Annandale, Camperdown, Forest Lodge and Harold Park, before spilling into Rozelle Bay, within Sydney Harbour.

Originally a natural watercourse, Johnston's Creek was converted into a brick and concrete channel in the 1890s in order to improve sanitation in Sydney[citation needed].

The creek rises in Petersham and initially marked the eastern boundary of the land granted to Lieutenant-Colonel George Johnston[1] in the 1790s, which he named Annandale.

[5] A salt marsh wetland was constructed in 2001 to filter storm water before it enters Sydney Harbour via Johnston's Creek.

[citation needed] In 2020 Sydney Water started a major project to naturalise the creek from The Crescent to the mouth at Rozelle Bay.