Trinity Island, Lough Key, Roscommon

Discover the History of Trinity Island

Hidden among the wooded islands of Lough Key, Trinity Island in Roscommon is one of the most historically important and visually striking locations in the lake. Rich in medieval history, mythology, monastic heritage, and natural beauty, the island has fascinated visitors, historians, and explorers for centuries. Today, Trinity Island remains one of the standout landmarks experienced on tours with Lough Key Boats.

Trinity Island was the site of the medieval Holy Trinity Abbey, one of two major religious foundations on Lough Key. The abbey was founded in the early 13th century by Clarus Mac Máilín, Archdeacon of Elphin, and became home to the Premonstratensian Order, also known as the “White Canons.”

In 1228, monks from nearby Boyle Abbey joined the community on Trinity Island after leaving Boyle Abbey. They brought important manuscripts and scholarly traditions which later contributed to the famous Annals of Lough Cé and Annals of Connacht — some of the most important historical records of medieval Ireland.

The abbey quickly became an important religious and intellectual centre in Connacht. Anglo-Norman forces also visited the island in 1235 before attacking the MacDermot stronghold on nearby Castle Island, highlighting Trinity Island’s importance during medieval conflicts.

Medieval Ruins on Trinity Island

Trinity Island, Lough Key

Today, visitors can still see the atmospheric ruins of Holy Trinity Abbey standing among the trees on the island. Archaeological excavations uncovered medieval tombs, coins from the reigns of Henry VIII and Elizabeth I, ancient graves, and evidence of monastic life dating back hundreds of years.

The abbey church originally featured a nave and chancel design with beautifully crafted stonework and lancet windows. Trinity Island also became the burial place of Sir Conyers Clifford, commander of the English forces defeated at the Battle of Curlew Pass in 1599.

Following the dissolution of the monasteries under Henry VIII in the 1530s, the abbey lands passed into the hands of the MacDermot family before eventually being confiscated by King James I in 1608.

Explore One of Ireland’s Hidden Historical Gems

Surrounded by calm waters, dense woodland, and panoramic lake scenery, Trinity Island offers visitors a glimpse into Ireland’s hidden medieval past. The island sits within the spectacular setting of Lough Key Forest Park, one of the most popular outdoor destinations in the west of Ireland.

The island is especially popular with:

  • History enthusiasts
  • Heritage tourists
  • Families visiting Lough Key
  • Photographers
  • Kayakers and boat tour visitors
  • Visitors exploring Ireland’s Hidden Heartlands

The peaceful atmosphere and dramatic ruins make Trinity Island one of the most memorable sights on Lough Key.

Trinity Island

Experience the magic, legends, and history of Trinity Island from the water with Lough Key Boats and discover one of Ireland’s hidden historical treasures.

Trinity Island

Trinity Island Boat Tours

One of the best ways to experience Trinity Island is from the water. Guided tours with Lough Key Boats allow visitors to explore the islands of Lough Key while learning about the myths, legends, monasteries, castles, and hidden stories that shaped the region over centuries.

From the lake, visitors enjoy incredible views of:

  • Trinity Abbey ruins
  • Castle Island and McDermott’s Castle
  • Ancient wooded islands
  • Historic monastic sites
  • Scenic lake landscapes and wildlife

Private tours and group experiences are also available for visitors seeking a more immersive historical and sightseeing experience around the islands of Lough Key.

Plan Your Visit to Lough Key

Trinity Island combines everything that makes County Roscommon special — rich heritage, untouched scenery, hidden history, and unforgettable views. Whether you are exploring Ireland’s Hidden Heartlands, planning a family day out, or discovering the stories of medieval Ireland, Trinity Island is one of the most fascinating places to visit on Lough Key.

Trinity Island, Lough Key

Frequently Asked Questions About Trinity Island, Lough Key

Trinity Island is a historic island located on Lough Key in County Roscommon. The island is best known for the ruins of Holy Trinity Abbey, a medieval monastery dating back to the 13th century.

Holy Trinity Abbey was a Premonstratensian monastery founded in the early 1200s. It became an important religious and scholarly centre in medieval Connacht and played a role in preserving important Irish historical manuscripts.

Trinity Island can primarily be viewed from the water during guided tours around Lough Key. Boat tours with Lough Key Boats offer visitors the opportunity to see the abbey ruins and learn about the island’s fascinating history.

The ruins of Holy Trinity Abbey date back to the 13th century, making them over 800 years old. Archaeological discoveries on the island have revealed medieval graves, coins, and evidence of monastic life.

Trinity Island was one of the major religious centres on Lough Key during medieval Ireland. Monks living on the island contributed to the preservation of Irish history through works such as the Annals of Lough Cé and the Annals of Connacht.

The abbey was founded by Clarus Mac Máilín, Archdeacon of Elphin, in the early 13th century for the Premonstratensian Order, also known as the White Canons.

Boat tours around Trinity Island offer views of:

  • Holy Trinity Abbey ruins
  • Nearby islands and castle
  • Scenic woodland landscapes
  • Historic monastic sites
    The beauty of Lough Key Forest Park

Visitors also learn about the myths, legends, and history connected to Lough Key.

Trinity Island is located within Lough Key in County Roscommon, Ireland, surrounded by the scenic landscapes of Lough Key Forest Park.

Yes, Trinity Island is considered one of the hidden historical gems of Roscommon. Its medieval abbey ruins, peaceful atmosphere, and rich heritage make it a popular destination for history lovers, photographers, and visitors exploring Ireland’s Hidden Heartlands.

The best way to experience Trinity Island is by water. Guided tours with Lough Key Boats provide a unique opportunity to explore the islands of Lough Key while learning about their history and legends.

Yes, boat tours around Trinity Island are suitable for families, couples, tour groups, and visitors of all ages looking to explore the natural beauty and heritage of Lough Key.

What People Say

Unforgettable Family Experience at Lough Key Boats
We had a wonderful experience with Lough Key Boats on Sunday, the 28th of September. The day was beautiful, and Catriona made it even more special. We first rented the boats and later decided to go on the speedboat tour, both experiences were absolutely amazing. With the rental boat, we were able to explore the lake and take time to see the island from a very close distance at our own pace. The speedboat tour then gave us a deeper appreciation of the lake’s history and beauty. We all left feeling so happy, and we want to say thank you for the fabulous memories across our whole family. We will definitely be back next summer!
Amazing trip
My father in law and his friend Bob from America had a lovely time in the boat with Catriona. She was very nice with them, she gave them a great tour around showing the place. She has so much knowledge. They highly recommend her and her team. Will do it again.
Above and beyond expectations!
This boat tour exceeded our expectations!! We booked it as McDermotts who wanted to just get close to McDermott castle, and we got so much more! Our guide, Oliver, was exceptionally knowledgeable about the island, the family, and the surrounding areas and he provided incredible insight into the history! We also were able to walk around the ruins of the monastery nearby. He also made sure to include the kids on some of the andventure and more. Even if you’re not a McDermott, this tour is sure to thrill and delight!
Magical Family Tour on Lough Key, A Must-Do!
We had a fantastic experience with Lough Key Boats! The tour was both relaxing and filled with fascinating stories that really captured the imagination of the kids. The staff were incredibly friendly, welcoming, and brilliant with children; they went out of their way to make the trip enjoyable for everyone. From castles and ancient monasteries to local wildlife, there were so many interesting nuggets of information shared along the way. A special highlight was the kids getting to sit in the captain’s chair; a moment they’ll remember! Highly recommend this for families visiting the area. A really lovely way to explore the beauty and history of Lough!