This dataset is a complete coverage of mapped and digitized Mountain Glaciation Trimlines landforms for Ireland.

This dataset forms part of the Quaternary geology of Ireland – Geomorphology Map which is a representation of Irish glacial geomorphological features at a scale of 1 to 50,000. The map shows categorised erratic carriage sources and sinks, subglacial lineations and striae, subglacial moraines, ice-marginal landforms and mountain glaciation corries and trimlines.

The Geomorphology dataset originally comprised individual feature layers that were subsequently merged from 25 single feature layers to 9 sub-groups, Mountain Glaciation Trimlines is one of the subgroups. This dataset contains a complete coverage for all mapped and digitised glacial trimline (ice free)areas, which were not glaciated during the last glaciation, for the island of Ireland.The map forms part of the GSI Quaternary Map series. Data recorded on the maps includes the locations of glacial trimlines, by their outlines. Other data include the county where the trimline occurs, the minimum altitude of ice, the digitised altitude, reference, name of he nunatak, and area which was ice free.The features have been compiled from a variety of sources, including academic papers, and the feature outlines were then drawn on OSi Colour Aerial Photography.