Online Historic Maps of Ireland

OSI – National Townland and Historic Map Viewer

GeoHive Alternate site (Updated)
Historical maps of Ireland, with a set of historical and current basemaps, also overlays of historic maps over more modern maps, with transparency and swipe options.
Taylor’s map of the environs of Dublin – 1816Taylor’s map of the environs of Dublin: extending 10 to 14 miles from the castle, by actual survey, on a scale of 2 inches to one mile, from McMaster University Library Digital Archive, Hamilton, Ontario, Canada
GeoHive mapsOrdnance Survey Ireland of Ireland, with historic maps from 1830s/40s, c1900s and c1930s, plus a number of modern Aerial map layers  (retired ? – Oct 2021)
Northern Ireland Historic mapsPRONI
Survey of the city and suburbs of Dublin 1757With the division of the parishes reduc’d from the large plan in four sheets by John Rocque, from Bibliothèque Nationale de France
An Exact Survey of the City and Suburbs of Dublin 1756In Which is Express’d the Ground Plot of all Publick Buildings Dwelling Houses, Ware Houses, Stables, Court Yards, &c, by John Rocque from Bibliothèque Nationale de France

1797 map of Dublin city, by John Neale (large jpeg image)
 Wikipedia Media
A Survey of the City, Harbour, Bay and Environs of Dublin 1757On the same Scale as those of London, Paris & Rome, by John Rocque from Bibliothèque Nationale de France
Modern Plan Of The City And Environs Of Dublin 1798Inscribed by Wm Wilson, engraved by B. Baker, Islington, from MAPCO
Map of Ireland 1838Compiled from the Surveys of the Board of Ordnance and other approved Documents By J. & C. Walker, from MAPCO
Dublin Historic Maps 1609-1797Section of Dublin Maps, mostly city area, which are overlayed over a modern Open Street Map. Use the slider control on the bottom right to set the
visibility of the modern map.
David Rumsey Map CollectionLarge Collection of maps
South Dublin County LibrariesLarge collection of Maps, focusing on South County Dublin and south city.
Old Maps OnlineMap Portal with links to various external websites
Placename Databasegives location on a modern map for townlands, parishes etc, plus additional details including spelling variations. (map coordinates for places in N.I. are given, but may not be as accurate) (www.logainm.ie) Also includes a selection of downloadable historic maps of Ireland, also an Ireland Gazetter, notes on Dublin Street names, Dublin History, a version of Lewis’ Topographical Dictionary of Ireland etc see : Toponymy resources
Various Historic maps of Ireland, Co. Dublin, Dublin City, Taylor & Skinner Road Maps 1777, Lewis 1837 County maps, etc