Nelly Bay Harbour sits on the southeastern shore of Magnetic Island, roughly 8 kilometres offshore from Townsville in Cleveland Bay.

It serves as the island's primary ferry terminal, linking the island to the Townsville Breakwater, and is the main arrival point for visitors and residents alike. Gustav Creek, the largest water catchment on Magnetic Island, flows approximately 3.

5 kilometres through the urbanised area of Nelly Bay before discharging into the harbour here.

A culvert at the creek's mouth marks the transition between the creek system and the harbour, and has historically required maintenance to manage sediment accumulation.

The creek has long been a gathering place for locals, who have used it for swimming, fishing, and recreation.