Greymouth is the largest town in the West Coast region on the South Island of New Zealand. The town is located at the mouth of the Grey River, on a narrow coastal plains close to the foot of the Southern Alps. In clear weather, Aoraki/Mount Cook can be clearly seen to the south from near the town.

It is on State Highway 6, which connects it with Hokitika in the south and Westport in the north. It also stands at the terminus of State Highway 7, which runs through Dobson and Reefton, eventually reaching north Canterbury and Christchurch via Lewis Pass. The town is also the western terminus of the Midland line from Christchurch. Large coal trains often operate from Greymouth on this line to Christchurch. The famous TranzAlpine train also terminates and begins in Greymouth.