Grosmont Castle was given to Hubert de Burgh by King John in July 1201, though its origins lies in the Norman annexation of the area. On Hubert’s death the castle reverted to the crown, becoming the property of the future king Edward I in 1254, and in 1267 to Edmund, Earl of Lancaster.
Grosmont Castle remained the property of the Duchy of Lancaster until 1825, and it was placed in State Guardianship in 1923.
C.A. Ralegh Radford’s paper guide consists of a history followed by a description. A plan was printed on p. 3.
Grosmont Castle is included in the Cadw guide for the Three Castles (Grosmont, Skenfrith, and White Castles) written by Jeremy K. Knight. This starts with a combined history for the three castles, followed by individual tours. There is also a short entry on Hen Gwrt Medieval Moated Site.