web analytics

Introduction to Tresco

Tresco - Isles of Scilly

The word Tresco means “Island of Elder Trees”, and in Cornish it is known as Enys Skaw.

Tresco is the second largest of the islands that make up the archipelago known as the Isles of Scilly after St Mary’s. It is approximately 1.5 square miles in are and measures roughly 2 miles by 1 mile.

In the twelfth century King Henry I gave the island to the community at Tavistock Abbey. They established a priory in place of the earlier Benedictine Abbey already on the island.  During the dissolution of the monasteries under King Henry VIII the priory was disbanded and the buildings fell into disrepair.

Currently the island is owned by the Duchy of Cornwall. However  the lease to the whole island is held by the Dorrien-Smith family who reside there.  They run the whole island as a holiday destination consisting of timeshare apartments and houses. They also run a variety of facilities for holiday makers to use.

Settlements on Tresco

New Grimsby on Tresco - Isles of Scilly

There are only two main settlements on Tresco: Old Grimsby, and New Grimsby.  Between them they include a convenience store with post office, a pub, two cafes, an art gallery and a health spa.

There are a number of quays on Tresco, one each in Old and New Grimsby, and one at the Southern end of the island at Carn Near.  These are necessary because of the shallow waters between the islands. This means that day trippers to the island need to need to be organized and know in advance which of the quays they will be picked up from or risk missing their boat.

The waters are shallow enough that several times a year it is possible to walk not only between Tresco and Bryher, but also between Tresco and St Martin’s.  You will likely get wet feet, but nothing worse than that.

Tresco Abbey

Tresco Abbey in its modern form

You can’t mention Tresco without talking about the Abbey and the Abbey Gardens.

The seventeen acre gardens were established by Augustus Smith, the nineteenth century proprietor of the islands.  They were orginally designed simply to be his personal gardens attached to his house.  A house he designed and built when he took on the lease of the islands.

He chose Tresco due to its central location in the archipelago, and the location itself due to the views over the beach at Carn Near, the fact that the original abbey ruins were there, and the freshwater lake.

One of his first acts was to wall off the site and plant gorse seeds from the mainland as the natiuve gorse did not grow high enough to provide shelter.

He also planted a variety of large trees, which identify Tresco easily from a distance.

Over time he, and his descendents acquired more and more unusual plants, until the garden became the unique place it is today.

It’s not just plants though, the Abbey Gardens on Tresco are home to a growing colony of red squirrels.  They were introduced in 2012, and due to the lack of predators like foxes, as well as the lack of grey squirrels and the diseases they carry they have thrived.

Tresco People

The population of the island has decreased fairly significantly over time. From 430 in 1841, down to 175 in the 2011 census.  Though this number is deceptive, as there are both a lot of seasonal workers on the island through the summer months.  And also there are a significant number of visitors, leading to the island feeling fairly busy at times.

Historical Tresco

Tresco Abbey Gardens

Just like all the other islands in Scilly Tresco has an absolute wealth of historical sites.  From the prehistoric to the modern.

One the Northwestern corner of the island, overlooking the narrow channel between Tresco and Bryher stand two of the most famous historical sites.

King Charles’s Castle

King Charles's Castle overlooking Cromwell's Castle

In the middle of the sixteenth century the threat of French invasion caused the islanders to build an artillery fort on the highest point overlooking the harbor at Old Grimsby. Made from granite with the living quarters behind the gun battery.

However it turned out that the site was not as suitable as first thought. From their position the guns were unable to cover the whole channel, and so a further blockhouse was built.

During the English Civil War Royalist forces held the islands, and men were stationed in the castle giving it its name.  But when Parliamentarian forces took the island the castle was destroyed by Royalists to prevent it falling into the hands of the invading forces.

Cromwell’s Castle

One of the most famous landmarks of the island of Tresco is Cromwell’s Castle.  It was built by Parliamentarian forces to replace the destroyed artillery fort known as King Charles’s Castle. It stands at the water’s edge with a much improved view of the whole sound and harbor.

The castle was constructed from the dressed stone scavenged from the former castle on the hillside above.

It stayed in service until shortly after the War of Jenkin’s Ear in the mid 1700s when it fell into disrepair.

The Old Blockhouse

The Blockhouse on Tresco

The Old Blockhouse is also know as Dover’s Fort, and stands overlooking both the harbor at Old Grimsby. It also views the anchorage known as St Helen’s Pool. Originally built to supplement the fort known as King Charles’s Castle, it sits on top of a natural rocky outcrop.

The old block house and the two castles are listed as scheduled monuments under UK law. They are currently managed by English Heritage and are free for visitors.


Just like the other islands, there is too much to cover on Tresco in a single article.  We will look at some of the specific things in much more detail soon.



Martin is the creator of About Scilly. He visited the islands for the first time 15 years ago and fell in love. He's been back every year since and would dearly love to live there.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Follow by Email