Lough na Suil | Mysterious Disappearing Lake of Irish Mythology
Updated: May 16
I first came to Moytura in Co Sligo in search of the places linked with the tales of Irish mythology upon which I was basing my books. Moytura, or Moytirra as it is still called today, is reputedly the site of the Second Battle of Moytura between the Tuatha de Danann and their long-time enemies, the Fomori.
Located between Geevagh and Riverstown in the townland of Ballinphuill, Lough na Suil (which means ‘Lake of the Eye’) lies on the edge of the battle site, not far from Heapstown Cairn.
It is said that once in every hundred years the lake mysteriously empties overnight and refills itself. Records show that this did indeed occur in 1833, 1933, and then at intervals of twenty years or so, until most recently in 2006 and 2012.
But is this due to magic and myth, or is there some other, more realistic explanation?
The most popular reason given for this sudden mysterious draining of the lake lies in the structure of the ground beneath it. The basin of the Lough rests in a karst limestone layer which is full of underground caverns and rivers. As water seeps through cracks and fissures in the limestone, they eventually widen over time to become sink holes. These holes often become blocked with mud, silt and other debris which on occasion collapses, causing the Lough to appear to empty almost overnight.
On my previous blog, the Woodland Bard, who lives locally and knows the area well added some interesting information in the comments; he wrote:
This lough has totally emptied a couple of times recently. Once at Charles Haughey’s death in 2006, Its emptied on the day of his death and its not a slow drain but like someone pulling a plug out. With that drainage the lough stayed empty for over 3 months. It actually became a pasture with cattle grazing. I kick myself now for not bringing home some of the grass turf samples. How many 100s, if not 1000s, of years had those seeds lay dormant below the lake before sprouting to become a pasture. When the water returned the fiddle playing pub and shop keeper and lough keeper Mary McDonagh passed away.
When the lough emptied that time to reveal the Balor hole again, Mary’s brother Des, who owned a pub down the road by Lough Arrow, turned up with a huge white stone and threw it down the hole … and told visiting tourists it was Balor’s eye 🙂
The lough then emptied again in 2012, which is very unusual, just 6 years later. Before then it had emptied roughly every 30 years since 1933 and every 100 years before that. Just before it emptied, Des McDonagh, he of the white stone eye, passed away. Mary and Des were both in their 80s though.
Now, I have never seen Lough na Suil so full. All this activity is strange considering the nearby pretty Lough Bo stays stable.
Although, in response, another commenter, Henry Barth claimed:
It wasn’t Mary McDonagh; she is alive (2015) and was Des’ wife. Des’ sister was Eileen McDonagh. Neither Des nor Eileen were in their 80s when they passed,
In mythology, Lough na Súil is where Danann High King and Master of All Arts, Lugh Lámfhada defeated his grandfather, the Fomori Giant-King, Balor of the Evil Eye. He killed him by famously throwing his spear (although some versions of the story claim it was a sling-stone) an incredibly long distance into Balor’s eye, thus earning himself the epithet ‘Long Arm’, or in Irish Lámfhada (pronounced La-wa-tha). Balor fell face down into the ground, his evil eye burning a great crater in the earth which filled up with water, and so the Lough was formed.
After the battle, Lugh cut off Balor’s head and hung it in a nearby hazel tree. Over the course of many years, the poison from his evil eye dripped down into the tree’s roots. Finally, the tree was overcome by the poison and split apart.
Seeing this, the sea god Manannán decided to harness the powerful properties of the wood and make a shield from it. Unfortunately, in the felling of the tree, eighteen men were killed by its poison, and a further nine killed as they fashioned the wood into the shield.
Manannán covered it with the skin of a sacred bull and marked it with druidic symbols, probably Ogham. Eventually, he gave the shield as a gift to Fionn mac Cumhall.
There is a Neolithic court tomb with a U-shaped court leading to a gallery of four chambers located on the battle site, known as The Giant’s Grave. The cairn infill material is long since gone, but the stone outline can still be seen. As Balor is the only giant mentioned in the mythology of the battle, it is quite possible that his body was carried here by his men and the cairn raised over him.
In 1929, Fr Sharkey, a local parish priest marked the 3000th anniversary of the Battle of Moytura by predicting the emptying of the Lough, and organised a huge festival in celebration of the event.
Unfortunately, the waters failed to recede to order, and the Lough did not drain until 1933, four years later. Apparently, a huge number of fish were found wedged in a muddy hole in the lake bed some fourteen feet deep, and consequently shared out amongst the astonished local population.