More on Grongar Hill from Infoplease:

• Grongar Hill - Grongar Hill in South Wales, has been rendered famous by Dyer's poem called Grongar Hill. ...
• John Dyer - Dyer, John Dyer, John, 1700?–1758, English nature poet, b. Wales. He is best known for the ...
• Dictionary of Phrase and Fable: G - Definitions, origins, and illustrative excerpts for words, phases, and literary allusions starting with "G"