Ordnance Survey of Great Britain 
The Ordnance Survey of Great Britain offers a range of products, from traditional walking maps and road atlases to large-scale maps and digital products.
Website: www.ordsvy.gov.uk
Ordnance Survey of Northern Ireland
The Ordnance Survey of Northern Ireland is responsible for providing mapping of the province of Northern Ireland.
Website: www.osni.gov.uk
Irish Lighthouse Service
The Commissioners of Irish Lights are the General Lighthouse Authority for all of Ireland, its adjacent seas and islands.
Website: www.cil.ie
Government of Ireland Website
This site will help you to find Irish government organisations or information, and also includes general information about Ireland.
Website: www.irlgov.ie
GeoDirectory
GeoDirectory is a joint project between An Post and Ordnance Survey Ireland. The GeoDirectory product is a database of every address in the State. It is a major infrastructural development which provides extensive benefits to businesses and users of GIS data.
Website: www.geodirectory.ie
Discover Ireland
Discover Ireland is operated by Fáilte Ireland, the National Tourism Development Authority, and features comprehensive information and listings for Irish accommodation, activities, events, tourist attractions and Irish holiday special offers. The Discover Ireland website is supported by a comprehensive home holidays media campaign throughout the year.
Website: www.discoverireland.ie