The Forth River is a significant tidal estuary and coastal waterway on Tasmania's Central North-West Coast, flowing into Bass Strait. It is a well-known destination for both inshore saltwater fishing and sea-run trout, forming part of the main sea-run trout fisheries on the northwest coast alongside the Mersey River. The river mouth and lower estuary are particularly popular for targeting large Australian salmon, while the upper tidal sections and brackish areas hold good populations of sea-run brown trout. The water is often having a tannin stain, and the system is influenced by substantial inter-basin water transfers from the Mersey catchment via Lake Parangana.