Derbyhaven (Manx: Camys y Ree, 'King's Harbour') was historically regarded as the Isle of Man's most important harbour due to its proximity to Castletown. Derby Fort, on the tidal St Michael's Isle guarding the harbour entrance, was built in 1645 by James Stanley, 7th Earl of Derby, replacing an earlier fort raised around 1540 under Henry VIII. Herring houses built in 1771 on the shore were used for salting and smoking the catch, reflecting the port's fishing heritage.