This dataset classifies the usual resident population of Wales, who were aged 3 and over, as at census day, 27 March 2011, by the ability to speak Welsh by national identity by sex and by age.

In order to protect against disclosure of personal information from the 2011 Census, there has been swapping of records in the Census database between different geographic areas, and so some counts will be affected. In the main, the greatest effects will be at the lowest geographies, since the record swapping is targeted towards those households with unusual characteristics in small areas.

More details on the ONS Census disclosure control strategy may be found on the Statistical Disclosure Control page on the ONS web site.