This dataset holds comprehensive habitat cover data for the whole of Wales derived from a programme of field recording that was begun by the Wales Field Unit (WFU) of the Nature Conservancy Council (NCC) in 1979 and continued by the Countryside Council for Wales (CCW) after restructuring in 1991. The purpose of this data capture was to inform site selection, casework and policy decisions. The lowland survey was particularly used to locate grassland sites suitable for more in-depth survey for notification purposes. Habitat extent data has been derived to inform the Local Biodiversity Action Plan process. The digitisation was carried out, in the first instance, for the drafting of maps for open country and registered common land as required by the CROW Act 2000. For reporting purposes during the lowland phase of the surveys, Wales was divided up into 15 different areas based on the Nature Conservancy Council's (NCC) Areas of Search (AoS). The dataset is unique, in that it holds full census field survey habitat data for the whole of terrestrial Wales. It has been used widely for research, advice and planning both within and outside CCW. The majority of the fieldwork was carried out 'in house' by closely co-ordinated teams of trained surveyors. Every effort was made to ensure consistency of habitat mapping. A check on surveyor accuracy during the early stages of the Phase 1 Survey revealed comparatively high repeatability levels (Kerry, S. M., Rimes, C. A., Smith, S. L. N., Williams, A. M. 1994. An assessment of errors in Phase 1 habitat survey in Wales. CCW report no. 94/4/1, Countryside Council for Wales, Bangor; Stevens, J.P., Blackstock, T.H., Howe, E.A., Stevens, D.P., 2004. Repeatability of Phase 1 habitat survey. J. Environ. Manage. 73, 53-59), and checks on the Upland Vegetation Survey data were carried out between 1994-1996 (Yeo, M.J.M., Blackstock, T.H., 2002. A vegetation analysis of the pastoral landscapes of upland Wales, UK. J. Veg. Sci. 13, 803-816). Digital maps were checked for accuracy at three stages: by contractor (Cynefin Environmental), and by CCW (C. Burrows, L. Howe, J. Stevens, J. Rothwell). 1km square table: the data were input and checked by a contractor (C. Copp) and re-checked by CCW (C. Burrows and J. Stevens). For a detailed overview of the background, methods and outputs of the Survey see Blackstock, T. H., Howe, E. A., Stevens, J. P., Burrows, C. R., Jones, P. S. 2010. Habitats of Wales. A comprehensive field survey 1979 -1997. University of Wales Press, Cardiff.