In 1819 Governor Macquarie decided to form an Agricultural Convict Establishment at Emu Plains which was closed in 1831. A part of this land was owned by John Mortimer who was the licensee of the Australian Arms Inn in 1841. The Inn is situated on the corner of the Great Western Highway and Gardenia Avenue Emu Plains (125-129 Great Western Highway). It is part of a larger property extending back to the railway line and boarded to the north by Nepean High School. In 1971 Penrith Council purchased the Inn and restoration plans lead to wide fundraising in the community coordinated by NDHS. The keys of the Arms of Australia Inn were handed over by the Mayor to the Inn committee in 1975. The Arms of Australia Inn was opened as a museum on 27 March 1976 by Sir John Fuller, Minister for Planning and Environment. It also became a meeting place for the Nepean District Historical Society.
