The National Gazetteer of Great Britain and Ireland - 1868
"SEATHWAITE, a hamlet and chapelry in the parish of Kirkby-Ireleth, hundred of Lonsdale North of the Sands, county Lancaster, 7 miles S.W. of Hawkshead, and 17 N.W. of Ulverston. It is situated in the vale of Dudden under the Old Man and other fells. The chapelry includes Seathwaite Tarn. The land is chiefly pasture, with some arable and meadow. The living is a perpetual curacy in the diocese of Carlisle, value £108."