Most of the records are from the period following the abolition of the Poor Law Union under the Local Government Act, 1929 when responsibility for the poor was transferred to the Public Assistence Committee of Anglesey County Council until the inception of the National Health Service in 1948. During that period the hospital used for this purpose was the Public Assistance Institution, Valley.
Some of the Volumes were used seamlessly from the Valley Workhouse of the Holyhead Union to the Public Assistence Institution, Valley to Valley Hospital.