Charlestown is a village and port on the south coast of Cornwall, England, in the civil parish of St Austell Bay. It is situated approximately 2 miles southeast of St Austell town centre. The port at Charlestown developed in the late 18th century from the fishing village of West Polmear. Whereas other areas of St Austell have seen much development during the 20t…Charlestown is a village and port on the south coast of Cornwall, England, in the civil parish of St Austell Bay. It is situated approximately 2 miles southeast of St Austell town centre. The port at Charlestown developed in the late 18th century from the fishing village of West Polmear. Whereas other areas of St Austell have seen much development during the 20th century, Charlestown has remained relatively unchanged.