State Department Registration
The U.S. State Department recommends that all U.S. citizens traveling abroad register their trip with the State Department trip registry. Registration is a free service and allows you to record information about your trip to Ireland and any other international travel you plan so that the Department of State can use it to assist you in case of an emergency. Americans residing abroad can also get routine information from the nearest U.S. embassy or consulate.
You may register your trip here: https://travelregistration.state.gov/ibrs/ui