page_title: County Meath
section_title: Geology
hierarchical_section_title: County Meath / Geography and political subdivisions / Geology
caption_attribution_description: English: Views from Loughcrew Passage Tomb near Oldcastle, County Meath Deutsch: Loughcrew bei Oldcastle, County Meath Euskara: Loughcrew Gaeilge: Loch Craobh Nederlands: Loughcrew Norsk nynorsk: Loughcrew Polski: Loughcrew Русский: Лох-Крю
context_page_description: County Meath is a county in Ireland. It is in the province of Leinster and is part of the Mid-East Region. It is named after the historic Kingdom of Meath. Meath County Council is the local authority for the county. At the 2016 census, the population of the county was 195,044. The county town of Meath is Navan. Other towns in the county include Trim, Kells, Laytown, Ashbourne, Dunboyne, and Slane.
  It is one of only two counties outside the west of Ireland to have an official Gaeltacht and the only county in Leinster to have an official Gaeltacht.
context_section_description: The county's geological landscape is predominantly made up of Lower Carboniferous limestone, which underlies approximately 75% of the county. These were laid down following the erosion of mountain ranges which formed due to the closure of the Iapetus Ocean. The eroded mountains became basins in which limestone sediments and carbonate mud were deposited. The oldest rocks in the county are Ordovician in age and are found in thin layers near Slane and at Stamullen, while the youngest rocks are of Paleogene age, and were formed as a result of volcanic activity. These are found in small dykes and sills throughout the county. Crustal stretching beneath Ireland during the Carboniferous allowed fluids to infiltrate through faults in the rock, and extensive mineralisation occurred. Most notably, zinc-bearing Sphalerite and lead-bearing Galena were deposited in vast quantities, giving Ireland the highest concentration of zinc per square kilometre on Earth. The ubiquity of these minerals gave rise to the term "Irish-type" lead-zinc deposits, which is a descriptive term for lead-zinc deposits hosted in carbonate rocks.
  Meath's landscape was shaped during the Last Glacial Period, which ended 11,700 years ago. The soils of the county are mostly derived from glacial till, consisting of a mix of clay, sand and gravel which were deposited by glacial melt-water. In the north of the county near the border with Cavan, a small series of drumlins were formed from boulder clay. Loughs typically form in between the poorly-drained inter-drumlin areas, however unlike in neighbouring Cavan and Westmeath, Meath has no sizable loughs, other than Lough Sheelin, on which the county shares a small coastline in its westernmost tip.
  Meath is largely flat and much of the county lies below 100 m (330 ft) above sea-level. The minor hills in the far west of the county at Loughcrew, and in the north at Carrickleck are the only upland areas of any significance. Slieve na Calliagh, at just 276 m (906 ft) in height, is the highest point in the county, making it the second lowest county top in Ireland. Carrickleck Hill, near the Cavan border, is the second highest peak in Meath, at 173 m (568 ft). The Hill of Tara is located south of Navan and, although just 155 m (509 ft) in height, is the most prominent feature in the local topography, commanding a panoramic view of the surrounding area.
caption: The Slieve na Calliagh hills
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