County Geological Site of the Month
County Geological Sites (CGSs) are the best examples of geological heritage in each county. They are promoted and protected by specific objectives contained within County Development Plans. CGS status is conferred as part of the County Geological Heritage Audit process.
Ireland is getting close to a national database for geological heritage sites, since 2007 25 counties, including the four Dublin Local authority areas, Cork City and Galway City Local Authority areas have been surveyed. Kerry is the only County remaining unaudited, and the last county to be completed in order to establish a national data set of geological heritage sites.
Each month we showcase an audited county geological site to highlight the diversity and depth of this aspect of our natural heritage.
Below you can find more information of the CGS of this month and previous months.
| Month | CGS Name | County | Description | Site Report |
June 2026 | Bricklieves/Keshcorran | Sligo | Keshcorran Hill and the surrounding drumlin fields clearly illustrates the glacial processes and lowering of the topography and karstbaselevels in the Keshcorran area | link |
May 2026 | Western Cuilcagh — Shannon Pot | Cavan | The very extensive network of water inputs from across the Cuilcagh range, indicates that extensive pre-glacial and inter-glacial development of drainage preceded all post-glacial developments | link |
April 2026 | Windy Gap | Louth | Windy Gap is a 200m-high mountain pass between the Slieve Foy (east) and Black Mountain(west) massifs | link |
March 2026 | Barnavave Quarry | Louth | The site is a small disused quarry on the eastern flank of Barnavave Hill, 200m above the upper road between Carlingford and Grange Irish | link |
February 2026 | Western Cuilcagh – White Father’s Caves | Cavan | The limestone hosting the cave is the Knockmore Limestone Member, a carbonate mudmound facies within the Dartry Limestone Formation, of Lower Carboniferous age | link |
January 2026 | Fowley’s Falls | Leitrim | The bedrock comprises Mississippian (Lower Carboniferous) interbedded limestone and shale of the Glencar Limestone Formation and shale and calcarenite of the Benbulben Shale Formation (c. 330 Ma) | link |
December 2025 | Bencroy | Leitrim | Bencroy is the most significant former coal mining site in the Connacht Coalfield east of Lough Allen | link |
November 2025 | Lough Kinale and Derragh Lough | Longford | The lakes lie in a trough of Lower Carboniferous limestone bedrock. They are separated by a peninsula area of well drained land, known as “Derragh Island” | link |
October 2025 | Glenbarrow | Laois | A long section in the bed and banks of the river in Glenbarrow | link |
September 2025 | Western Cuilcagh – Corratirrim | Cavan | The rock here are limestones belonging to the Lower Carboniferous Dartry Limestone Formation. They are mudbank facies defined as the Knockmore Member | link |
August 2025 | Mongan Bog | Offaly | Mongan Bog comprises an extensive area of peatland extending in a lowlying hollow for approximately 2 kilometres, north to south, just east of Clonmacnoise. | link |
July 2025 | Corlea Trackway | Longford | The Corlea Trackway is situated within an area dominated by bedrock of Lower Carboniferous limestone | link |
June 2025 | Abbeyleix Bog | Laois | Abbeyleix Bog comprises an extensive area of peatland extending in a low-lying hollow | link |
May 2025 | Little Brosna – Shannon Confluence | Offaly | The Little Brosna is confined by raised bogs with callows along its final 8km | link |
April 2025 | Murrens Esker | Meath | The site consists of a wooded ridge – esker and hummocky ground including gravel pit | link |
March 2025 | Temple Bar Street Well | Dublin | The well is a hydrogeological feature of historic and perhaps modern water flow | link |
February 2025 | Clogher Head | Louth | This is an approx. 750-long coastal section, between Port Oriel in the north and Red Man’s Cove in the south, comprising extensive foreshore outcrops backed in places by steep cliffs | link |
January 2025 | Dunmore Cave | Kilkenny | Impressive dripstone formations are found throughout this cave system, including numerous stalactites and stalagmites ranging from a few millimetres to several metres in size | link |
December 2024 | Clonkeen Mushroom Rock | Offaly | Clonkeen is one of the relatively numerous examples of mushroom rocks in Offaly | link |
November 2024 | Lough Boora Parklands | Offaly | The Lough Boora Parklands are situated within an area dominated by bedrock of Lower Carboniferous limestone | link |
October 2024 | Knocknarea | Sligo | Fossils are found in the outcrops on this hill, which was shaped by glacial processes | link |
September 2024 | Ballymastocker Bay | Donegal | Ballymastocker Bay is a wide coastal beach and dune system with some unusual exposures of bedrock and cemented sand dunes | link |
August 2024 | Boyne Valley | Meath | Features within the valley include suites of glaciofluvial and delta terraces. | link |
July 2024 | Cuilcagh Mountain | Cavan | As sea-levels fell in the Carboniferous, limestone seas were filled with sand and mud to form these Cuilcagh Mountain rocks | link |
June 2024 | Ballydonegan Strand | Cork | This unusual beach is essentially man-made, formed as a direct consequence of copper mining, mainly in the 19th century. | link |
| April 2024 | Lady’s Island Lake | Wexford | Geomorphology has a direct influence on this brackish lagoon which is an important habitat for many species of birds. | link |
| March 2024 | Silver River | Offaly | Follow the Silver River gorge through the Silurian, Devonian and Carboniferous along this nature trail | link |