Old Blockhouse

Aerial View of Old Blockhouse with beaches in foreground
View past corner of Old Blockhouse towards the golden beach and across the sea, islets and islands
The exterior of the Old Blockhouse.

Free Entry

Open any reasonable time during daylight hours


Tresco, Isles of Scilly, TR24 0QW

Before You Go

Built in the 16th century to protect Old Grimsby Harbour, the Old Blockhouse saw action in the late stages of the Civil War, when Parliamentarians attacked the Royalist garrison.  Today its substantial remains overlook a white sandy beach.

Read more about the history of the Old Blockhouse.

Before You Go

Access: The blockhouse is only accessible on foot, via a 20 minute walk from Old Grimsby along pleasant lanes.

Dogs: Dogs on leads are welcome.

Please be aware: English Heritage does not permit drone flying from or over sites in our care, except by contractors or partners undertaking flights for a specific purpose, who satisfy stringent CAA criteria, have the correct insurances and permissions, and are operating under controlled conditions.

There are steep and uneven steps up to the Blockhouse entrance, with sheer drops from inside the ruins.


Plan a Great Day Out

Refreshments are available from a well-stocked shop just south of New Grimsby harbour - why not put a picnic together and enjoy it on the vast white sandy beach.

Take time to discover the island's two castles on the western side of the island. Cromwell's Castle and King Charles' Castle are situated just north of New Grimsby Harbour. Along with the Old Blockhouse, these two sites can be included on the six mile circular coastal walk around Tresco.

Call in at the Isles of Scilly Museum in Hugh Town, St Mary's, for more information about the history of the Isles.


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Your membership provides valuable support for our essential work, while you can enjoy free access to the beauty and inspiration of our magnificent historic places. 


About us

English Heritage cares for over 400 historic buildings, monuments and places - from world-famous prehistoric sites to grand medieval castles, from Roman forts on the edges of empire to a Cold War bunker. Through these, we bring the story of England to life for over 10 million people each year. The English Heritage Trust is a charity, no. 1140351, and a company, no. 0744722, registered in England.

How We Are Funded

Our target is to become completely self-funding by 2023. Our confidence in achieving this is based on our track record. During the past 10 years, our commercial income has doubled and we have raised nearly £60m in donated income.

  • 66% Self-generated income
  • 20% One off capital grant
  • 14% Government funding
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