Gasholder present South of the original gasworks, west of Old Station Road on the 1924 OS map. This site became the location of a new gasworks. There was a reference from July 1946 which referenced a "New Works Site", 11a conveyed to O. R. Jones. In 1949 the annual gas productions at that time, were Holyhead - 102 m cu.ft.. Vested in the Wales Gas Board from the Holyhead and North Wales Gas and Water Corporation Ltd, Holyhead Undertaking. In 1952 the “Gas World Year Book”, showed that Holyhead was manufacturing 100 m cu.ft. of gas using vertical retorts. A.I. Jones was the manager. The plan of the gasworks in from 1953 showed the gasworks to consist of a retort house (vertical), Scrubber house, purifiers, exhauster house, boiler house, mess room, meter, and booster house, benzole house, test room laboratory and condensers. By 1953 the "old gas works" site contained only offices and a governor house. By 1961 the site had been used for a Service Centre, the station governors being at the works further south. The gasworks were visible on the 1923 to 1995 OS maps.