Aims and scope The European Alien Species Information Network team (EASIN, http://easin.jrc.ec.europa.eu) of the Joint Research Centre (JRC) requested the European member states on 22 June 2016 at the 6th IAS Committee to verify the baseline distribution data (2017) of invasive alien species of Union Concern (37 species) as provided by the EASIN mapping system (Katsanevakis et al. 2012). These are species with documented biodiversity impacts sensu the European Union Regulation on the prevention and management of the introduction and spread of Invasive Alien Species in Europe (IAS Regulation No 1143/2014) (European Union 2014). The purpose of this baseline was to set a representative geographic account of the current distribution of these species at (i) country and (ii) 10km 2 grid level and to get feedback from the member states on this. This distribution provides the baseline for subsequent reporting by the member states as required by the IAS Regulation. The dataset provides a shapefile on the baseline ... :