Silloth is a port town and civil parish in Cumberland, Cumbria, England. Historically in the county of Cumberland, the town is an example of a …Silloth is a port town and civil parish in Cumberland, Cumbria, England. Historically in the county of Cumberland, the town is an example of a Victorian seaside resort in the North of England. Silloth had a population of 2,932 at the 2001 Census, falling slightly to 2,906 at the 2011 Census.