Olderfleet Castle lies in the harbour area of the city of Larne, in County Antrim, in Northern Ireland. On a map from 1610 it was called Coraine Castle. It is now named after a former name of Larne Lough.
Olderfleet Castle is said to have been built by the Scottish Bisset family in the 13th century. In 1315 Edward Bruce, the last High King of Ireland, landed here with his 6000-man strong army of Scots to conquer Ireland.
In 1569 Sir Moyses Hill was appointed governor of Olderfleet Castle by Queen Elizabeth I to defend it against the Scots. He fortified the castle. In 1597 the castle was claimed by Sorley Boy Mcdonnell and in 1598 it was dismantled.
The present castle was probably built by Sir Arthur Chichester in 1612 to replace its predecessor. Its square remains however show that it only had 1 meter thick walls and there are no visible domestic features. This leads to believe that it was built as a fortified warehouse and watchtower. It is believed to have been 4 storeys high and has gun loops on the ground floor. It resembles a tower house and was one of three castles that once guarded the harbour of Larne in Larne Lough.
In 1798 Olderfleet Castle and the town of Larne were attacked by the Rebels.
This is a small, not very spectacular, ruin in an industrial area.