LHBs were first established in Wales in 2003. They were 22 in number, being coterminous with the 22 Welsh local authorities. The LHBs were subsidiary to a system of NHS Trusts. This was found to be an unnecessarily complex structure. Simplification began by the merging of the Trusts, eventually reducing the number to 7 by October 2009, at which time a major reorganisation was implemented.
In essence the LHBs were abolished, their functions being subsumed by the 7 NHS Trusts. Confusingly the Trusts were described in law as 'Local Health Boards' despite the fact that in general they were now to be more regional than local in nature. This confusion has been exacerbated by the fact that all 7 LHBs have chosen operational names (i.e. the names by which they are known to the public) which specifically omit the word 'local'. The term 'Local Health Board' is thus no more than a legislative description.
Note that the name 'Trust' has been adopted/retained by three 'all-Wales' units within NHS Wales.