St Paul's Hospital originally opened in 1836 as the workhouse for the Hemel Hempstead Union, which consisted of the parishes of Bovingdon, Flaunden, Great Gaddesden, Hemel Hempstead and Kings Langley . The workhouse had an infirmary with 224 beds to house patients who were aged, infirm or chronically ill. The workhouse and infirmary were situated in Allendale Road in Hemel Hempstead. From April 1930 under the Local Government Act 1929, responsibility for the workhouses, including workhouse infirmaries, passed from the Boards of Guardians to the County Council's Dacorum Guardians Committee, which was responsible for the area of the former Hemel Hempstead Union plus part of the former Berkhamsted Union. The workhouse became known as Hempstead House. In May 1936 the Berkhamsted workhouse closed and Hempstead House became responsible for the poor, including the sick poor, of the entire Dacorum Guardians Committee area. During the Second World War it was occupied by the evacuated section of Great Ormond Street Children's Hospital in London. In February 1942 there were 106 evacuated children there.
The building became part of St Paul's Hospital after the war, then part of Hemel General, but was demolished several years ago and the site is now housing.