In 1887, John Bartholomew's Gazetteer of the British Isles described Dunster like this:
Dunster, market town and par. with ry. sta., W. Somerset, 5 miles W. of Watchet, 3455 ac. (585 water), pop. 1126; P.O., T.O., 1 Bank. Market-day, Friday. In vicinity is Dunster Castle, built in the 16th century, on the site of an older work of the 11th century; 1 mile S. is Dunster Park.
GB Historical GIS / University of Portsmouth, History of Dunster in West Somerset | Map and description, A Vision of Britain through Time.
Date accessed: 22nd March 2017
Click here for more detailed advice on finding places within A Vision of Britain through Time , and maybe some references to other places called " Dunster ".