Game of Thrones has been filming in various locations around the Mourne Mountains. In Season One episode four the entry to Vaes Dothrek
was filmed below Slievemageogh just of the Sandy Brae track. Check out the link below in the Vaes Dothrek tab.
I also believe that some scenes were filmed at Leitrim Lodge but as yet that has not been confirmed. If anyone knows of
locations that have been used please send me the details/photos and I will include them on the web site.