While my Department collates and publishes a wide range of housing statistics, the full extent of which can be viewed at http://www.environ.ie/en/Publications/StatisticsandRegularPublications/HousingStatistics/ it does not collect the data sought on the number of vacant local authority housing units by local authority area. However, information relating to vacant local authority housing is available in the Annual Service Indicators in Local Authorities Reports which are prepared by the Local Government Management Agency (LGMA). The most recent report, in respect of 2012, and reports for previous years are available on the LGMA website at the following link: http://www.lgcsb.ie/en/publication-category/service-indicator-reports-2004-2010.