Grosnez Castle is one of those enigmatic places. On the one hand, from the ruins we must deduce that a castle of some size was build on the Grosnez headland, and it must have been quite magnificent judging from the ornate carved stonework. On the other, we really don’t know exactly when it was built (probably around the 1330s) nor when it was pulled down (perhaps during the French occupation in the 1460s?). On every old map of the Island known to exist, even those which are over 500 years old, Grosnez Castle is described as being in ruins. We don’t even know exactly what its original purpose was, and the debate is whether it was intended only as a place of temporary refuge in case of attack or whether it could have withstood a siege like Mont Orgueil in the east.
The one thing which is certain, however, is that its location is spectacular with views to all the other Channel Islands on a clear day. For that reason, when signal stations were build in the 19th century by General Don to communicate with troops across all the Islands, one was sited on the cliffs at the Castle.