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An tSlí Mhór (The Great Way) and the Esker Riada

 

 

Thoughts on how and why some of Ireland’s present-day roads have been used for several thousand years.

 

This map shows that part of the old Dublin-Galway route connected monastic sites, like Durrow and Clonmacnoise in Offaly, which are both a little south of the present-day N6.

Three parishes (Esker (An Eiscir), Co. Dublin; Moylisker (Maoileiscir), Barony of Fartullagh, Co. Westmeath and Ahascragh (Áth Eascrach), Co. Galway) and circa 74 townlands across the island of Ireland contain the word esker, eiscir or eascrach, or a variation thereof.

This means that they are wholly or partly comprised of an esker: a long, meandering ridge of sand, gravel and boulders formed by deposits that were revealed by the melting of the glaciers of western Europe approximately 15,000 years ago.

A rough head of esker townland names places County Galway (22) in first place, followed by Mayo (12), Tyrone (8), Offaly (4), Tipperary (3), Laois (3), Kildare (3), Fermanagh (2), Dublin (2), Leitrim (3), Westmeath (1) and Monaghan (1). Fuller details of these townlands follow below.

Eskers were probably considered safer walking routes in the past, being higher and drier underfoot than surrounding boggy areas, with a gravelly base formed from stone deposits at the end of glaciers.

Like ridgeway paths everywhere, they would also have afforded good vantage points for identifying destinations in the distance, plot routes and potential hazards. Settlements and paths would naturally have evolved along these walkways, so that, in time, the roads inevitably followed the same route to connect all these towns and villages.

One such ridegway may have been used as a road by the first settlers in Mesolithic Ireland to traverse the country. The settlement at Lough Gur near Limerick stood on high grounds above what would have been wet lands after the ice age. Another early transport route was the “Ridge Road” that ran along the dry summit of an esker between Portlaoise and Mountmellick.

According to the Annals of the Four Masters, a war between Conn of the Hundred Battles and Eoghan Mór in 123AD was concluded when the rival kings  agreed to create a north-south dividing line between their kingdoms, namely “Leath Cuinn” (Conn’s Half) and “Leath Mogha” (“Mogha’s Half”). This border evolved into an ancient highway known as An tSlí Mhór (The Great Way) or, in Latin, as Via Magna. This trade and pilgrimage route ran between the Áth Cliath Cualann hurdle ford (from which Dublin derives its Irish name) and the Áth Cliath Maree at the mouth of the Clarin River on Galway Bay.

The Horseleap Esker running along the blue line is one of a group of eskers (Moate, Split Hill, Clara, Ballyduff, Kilcormac) that converge eastward in a large fan shape. It is bisected by the R391 road and by the Midland Great Western Railway (Clara Branch) line, which closed in 1965. The McGeoghegan clan built a castle atop, now in ruins. There seems to be no surviving pathway, while there is a quarry at Ardnurcher. The Bianconi horse route overlaps some of this. (See here).  With thanks to John Casey.

An tSlí Mhór was one of the five great roads of Ireland, all of which connected to the royal palace at Tara. The Dublin towns it passed through were Celbridge, Lucan (where the parish of Esker is found), Adamstown, Palmerstown and Chapelizod. It might be noted that Greenhills Road seemingly formed part of an esker that ran via Crumlin into Dublin city centre. Tymon Castle, now a ruin, was pitched on top of this esker, while the the National Basketball Arena is there now.

Parts of An tSlí Mhór have been incorporated into the main N6 Dublin to Galway road, which follows part of the Esker Riada, a sequence of eskers running across the boggier lands of central Ireland. The eskers are especially noticeable when the N6 passes through South Westmeath and North Offaly. For example, there is an esker between Tyrellspass and Kilbeggan on the north side of the N6, which was, and is, a good walking pathway. A couple of miles south of the N6, in Offaly, there is the Esker Rí, the Clara Esker, while three eskers are thought to meet around Tullamore, including the site of the Esker Hills Golf Club

The townland of Garrisker refers to an esker, just south of the old main road near Broadford, Co. Kildare

The highway joined the Esker Riada near Clonard, County Meath, just east of Kinnegad, where the present-day N4 / M4 from Dublin joins the N6/ M6 to Galway. By and large, the highway then followed the Esker Riada west via Moate and Athlone all the way to County Galway.

The River Shannon cuts through the route close to the centre of Ireland, effectively quartering Ireland. It is no coincidence that Athlone is on an esker, as are the abbeys of Clonmacnoise and Durrow, both a little south of the N6, all of which were connected to the old Dublin-Galway route. The site of Clonmacnoise was specifically chosen because it was at the junction of the north-south route on the navigable River Shannon and the Great Way, the main east-west route across Early Christian Ireland. As mentioned above, St Finian’s monastery, seemingly founded at Clonard circa 520, was also located off an esker.

The East Galway parish of Ahascragh (Áth Eascrach) appears to be named for a river crossing in an area of esker ridges.  From Athenry, An tSlí Mhór crossed a significant esker near Aughrim, close to the old coach road. It also passed through Ballinsaloe before reaching Clarinbridge in County Galway. A trail outlined by Moycullen Heritage (here) showed how the eskers extend past Galway into Connemara on the west side of Lough Corrib, with an esker that runs for 6km from  Tullokyne to Killannin.

 

The Fate of the Esker Riada

 

Courtesy of Wesley Johnson, here.

While some of the Esker Riada remains part of the main road today, its fate was somewhat sealed by it being such a rich source of building materials, not least as the various deposits were so well sorted and layered by the sub-glacial riverine action of water. Much of the the Esker Riada has thus been quarried and / or mined.

For instance, a large quarry has been cut through part of the western portion of the Ballinasloe Esker, while there is another quarry at Ardnurcher on the Horseleap Esker. The Athenry Esker is home to Esker Readymix, which started selling sand, gravel and filling back in 1950. Most of the Rathmoylon Esker in County Meath had been quarried. Likewise, most of the Ridge of Maryborough in County Laois has been removed on the southern outskirts of Portlaoise, while only two of the five segments of the Timahoe Esker remain intact.  On the other hand, in 2022, Offaly County Council refused planning approval for a quarry that proposed to extract 200,000 tons of sand and gravel on 3.2 hectares of lands at Esker More, Mount Lucas, Tullamore.

Newer road routes are a combination of engineering and politics, with local TDs pushing for new roads to come closer to their spheres of influence, which would account for some of the differences from esker pathways and monastic routes.

The Dublin-Galway railway line does not seem to follow esker ridges very closely, other than to serve towns that sprang up along the esker routes, but engineering a railway line on flatter land was assuredly easier than running it along esker ridges,

 

Acknowledgments

 

With thanks to Helen Gallagher, Derek Ryan, Christoper McQuinn, Aisling Gearailt, John Casey, Rian Ó Murchadha, John McKenna, Gordon White, Klaus Göttsche, Lucinda Blyth, Robert L Laffan, Andrew Whiteside, Walter McDonagh, Nativeguide, Hazel Morrison Pagett, Kevin Clarke, Paul Cuddihy, Sean Connell, Alan Gilbert and Mary Coakley.

 

Further Reading

 

  • Hermann Geissel, ‘A Road on the Long Ridge: In Search of the Ancient Highway on the Esker Riada’, here.
  • Ruby Wallis, Joe Laverty and Aidan O’Neill, ‘Re-imagining a Line (in search of the Esker Riada)’

 

Esker Townlands

 

  1. Ahascragh East, Ahascragh Civil Parish, Barony of Kilconnell, Co. Galway
  2. Ahascragh West, Ahascragh Civil Parish, Barony of Kilconnell, Co. Galway
  3. Ballinesker, St. Margaret’s Civil Parish, Barony of Shelmaliere East, Co. Wexford
  4. Ballynaheskeragh (Baile na hEiscreach) , Killimorbologue Civil Parish, Barony of Longford, Co. Galway
  5. Barnahesker (Barr na hEiscire) , Aghamore Civil Parish, Barony of Costello, Co. Mayo
  6. Belesker (Béal Eiscreach) , Bekan Civil Parish, Barony of Costello, Co. Mayo
  7. Caherfinesker (Cathair Fhinneiscreach) , Athenry Civil Parish, Barony of Athenry, Co. Galway
  8. Clashaniskera (Clais an Eiscire) , Modreeny Civil Parish, Barony of Lower Ormond, Co. Tipperary
  9. Clonascra (Cluain Eascrach) , Clonmacnoise Civil Parish, Barony of Garrycastle, Co. Offaly
  10. Cloonascragh (Cluain Eascrach) , Kilbennan Civil Parish, Barony of Dunmore, Co. Galway
  11. Cloonascragh (Cluain Eascrach) , Clontuskert Civil Parish, Barony of Longford, Co. Galway
  12. Clooneskert, Kilteevan Civil Parish, Barony of Ballintober South, Co. Roscommon
  13. Coolacheesker, Clonmeen Civil Parish, Barony of Duhallow, Co. Cork
  14. Coolesker, Barony of East Omagh, Co. Tyrone
  15. Derryesker (Doire Eiscreach) , Rahan Civil Parish, Barony of Ballycowan, Co. Offaly
  16. Esker, Dromore Civil Parish, Barony of East Omagh, Co. Tyrone
  17. Esker (Eiscir) , Clonfert Civil Parish, Barony of Longford, Co. Galway
  18. Esker (An Eiscir) , Youghalarra Civil Parish, Barony of Owney and Arra, Co. Tipperary
  19. Esker (An Eiscir) , Clonenagh and Clonagheen Civil Parish, Barony of Maryborough West, Co. Laois
  20. Esker (An Eiscir) , Lemanaghan Civil Parish, Barony of Garrycastle, Co. Offaly
  21. Esker, Taghmaconnell Civil Parish, Barony of Athlone, Co. Roscommon
  22. Esker, Moylough Civil Parish, Barony of Tiaquin, Co. Galway
  23. Esker, Mothell Civil Parish, Barony of Fassadinin, Co. Kilkenny
  24. Esker, Ballymacward Civil Parish, Barony of Tiaquin, Co. Galway
  25. Esker (An Eiscir) , Cloone Civil Parish, Barony of Mohill, Co. Leitrim
  26. Esker (An Eiscir) , Kilconduff Civil Parish, Barony of Gallen, Co. Mayo
  27. Esker (An Eiscir) , Fossy or Timahoe Civil Parish, Barony of Cullenagh, Co. Laois
  28. Esker (An Eiscir) , Knock Civil Parish, Barony of Clanmorris, Co. Mayo
  29. Esker (An Eiscir) , Kiltullagh Civil Parish, Barony of Athenry, Co. Galway
  30. Esker (An Eiscir) , Errigal Trough Civil Parish, Barony of Trough, Co. Monaghan
  31. Esker Beg (An Eiscir Bheag) , Ballynakill Civil Parish, Barony of Coolestown, Co. Offaly
  32. Eskerboy (An Eiscir Bhuí) , Abbeygormacan Civil Parish, Barony of Longford, Co. Galway
  33. Eskerbuoy (An Eiscir Bhuí) (aka Eskerboy) , Termonmaguirk Civil Parish, Barony of East Omagh, Co. Tyrone
  34. Eskeradooey, Cappagh (Upper Strabane portion) Civil Parish, Barony of Strabane Upper, Co. Tyrone
  35. Eskeragh, Aghalurcher Civil Parish, Barony of Magherastephana, Co. Fermanagh
  36. Eskeragh (Eiscreach) , Crossmolina Civil Parish, Barony of Tirawley, Co. Mayo
  37. Eskerballycahill, Killosolan Civil Parish, Barony of Kilconnell, Co. Galway
  38. Eskerbaun, Cam Civil Parish, Barony of Athlone, Co. Roscommon
  39. Eskerbeg, Taghmaconnell Civil Parish, Barony of Athlone, Co. Roscommon
  40. Eskerhill, Harristown Civil Parish, Barony of West Offaly, Co. Kildare
  41. Esker Island (Oileán Eascrach) , Clonfert Civil Parish, Barony of Longford, Co. Galway
  42. Esker East (An Eiscir Thoir) , Crossboyne Civil Parish, Barony of Clanmorris, Co. Mayo
  43. Eskerkeel (An Eiscir Chaol) , Clontuskert Civil Parish, Barony of Clonmacnowen, Co. Galway
  44. Eskerlevally (Eiscir Leathbhaile) , Kilcolman Civil Parish, Barony of Clanmorris, Co. Mayo
  45. Eskermore (Eiscir Mor) , Clogher Civil Parish, Barony of Clogher, Co. Tyrone
  46. Eskermore, Clogherny Civil Parish, Barony of East Omagh, Co. Tyrone
  47. Eskermore, Ahascragh Civil Parish, Barony of Killian, Co. Galway
  48. Esker More (An Eiscir Mhór) , Ballynakill Civil Parish, Barony of Coolestown, Co. Offaly
  49. Eskermurry (Eiscir Uí Mhuirígh) , Killeroran Civil Parish, Barony of Killian, Co. Galway
  50. Eskernabrogue (Eiscir na mBróg) , Clogher Civil Parish, Barony of Clogher, Co. Tyrone
  51. Esker North (An Eiscir Thuaidh) , Crossboyne Civil Parish, Barony of Clanmorris, Co. Mayo
  52. Esker North (An Eiscir Thuaidh) , Esker Civil Parish, Barony of Newcastle, Co. Dublin
  53. Esker North (An Eiscir Thuaidh) , Killoe Civil Parish, Barony of Longford, Co. Longford
  54. Esker North, Mohill Civil Parish, Barony of Mohill, Co. Leitrim
  55. Eskeromullacaun, Boyounagh Civil Parish, Barony of Ballymoe, Co. Galway
  56. Esker (part of), Meelick Civil Parish, Barony of Gallen, Co. Mayo
  57. Eskerroe, Killoscobe Civil Parish, Barony of Tiaquin, Co. Galway
  58. Eskerroe (An Eiscir Rua) , Kilcloony Civil Parish, Barony of Clonmacnowen, Co. Galway
  59. Esker South (An Eiscir Theas) , Crossboyne Civil Parish, Barony of Clanmorris, Co. Mayo
  60. Esker South (An Eiscir Theas) , Killoe Civil Parish, Barony of Longford, Co. Longford
  61. Esker South (An Eiscir Theas) , Esker Civil Parish, Barony of Newcastle, Co. Dublin
  62. Esker South, Mohill Civil Parish, Barony of Mohill, Co. Leitrim
  63. Eskerymorilly (Eiscir Uí Mhuraíle) , Knock Civil Parish, Barony of Clanmorris, Co. Mayo
  64. Eskershanore (Eskershanore) , Kilchreest Civil Parish, Barony of Loughrea, Co. Galway
  65. Eskragh (Eiscreach), Clogher Civil Parish, Barony of Clogher, Co. Tyrone
  66. Eskragh(Na hEiscreacha) , Kilmacteige Civil Parish, Barony of Leyny, Co. Sligo
  67. Eskragh (Eiscir) , Donaghmore Civil Parish, Barony of Dungannon Middle, Co. Tyrone
  68. Fisherstown (Gráig an Eiscire) , Lea Civil Parish, Barony of Portnahinch, Co. Laois
  69. Forthill (Cluain Eascrach) , Bekan Civil Parish, Barony of Costello, Co. Mayo
  70. Garrisker, Ballynadrumny Civil Parish, Barony of Carbury, Co. Kildare
  71. Letterdeskert (Leitir Deiscirt) , Moyrus Civil Parish, Barony of Ballynahinch, Co. Galway
  72. Killescragh(Cill Eiscreach) , Killimordaly Civil Parish, Barony of Athenry, Co. Galway
  73. Kylenaheskeragh(Coill na nEiscreach), Ballygibbon Civil Parish, Barony of Upper Ormond, Co. Tipperary
  74. Mullymesker, Cleenish Civil Parish, Barony of Clanawley, Co. Fermanagh
  75. Rathesker (Ráth Oscair) (aka Rathesker), Naas Civil Parish, Barony of North Naas, Co. Kildare
  76. Riversdale(Coill na hEiscreach) , Killeroran Civil Parish, Barony of Killian, Co. Galway
  77. Sheskernagh, Rathgarve Civil Parish, Barony of Fore, Co. Westmeath
  78. Tiranascragh (Tír Chinn Eascrach), Tiranascragh Civil Parish, Barony of Longford, Co. Galway