President Mary McAleese goes on RTÉ Radio on September 11, 2001, to express her shock and horror at the terrorist attacks in the United States.

The President says that these atrocities are “crimes against the very foundations of our humanity.” She comments that “it is unbearable and almost unbelievable for the rest of the world to be witnessing such wanton destruction of human life in front of our eyes.”

President McAleese speaks by telephone with the United States Ambassador to Ireland, Richard Egan, and asks him to convey to President George W. Bush the heartfelt sympathies of the Irish people in this hour of great tragedy for the people of America, a nation which Ireland holds so dear.

The Irish government names more than a dozen of its natives among the dead in New York City, Washington, D.C., and Pennsylvania. Based on family names and individual stories, there are many hundreds of American dead with Irish heritage, including Americans who through parents or grandparents have become Irish citizens.

The website www.IrishTribute.com, set up in reaction to the September 11 attacks, estimates that perhaps one-sixth of the dead are in some way “Irish.” The website claims that “September 11, 2001 may well go down as the bloodiest day in the history of the Irish people. An estimated 1,000 people who were of Irish descent or of Irish birth were lost in the violent events on that day.”

A National Day of Mourning is held in Ireland on September 14 and a remembrance mass is held on September 12, 2001. Ireland is one of the few countries to hold a service day. Taoiseach Bertie Ahern and President McAleese are both in attendance.

Families in Limerick take in American tourists grounded at Shannon Airport after all flights into and out of the United States are cancelled.

The only flag, other than the U.S. flag, to fly at the Ground Zero site is the Irish tricolour, which is put in place by the Carpenters Union #608 and FDNY Command Post.

In the wake of the attacks, the Irish government immediately begins reviewing security arrangements.