Are you an Irish citizen travelling to the USA? You may need a visa.
Irish citizens who hold a valid machine readable passport and who have acquired Electronic System for Travel Authorization (ESTA) approval may be eligible for the Visa Waiver Program. The Visa Waiver Program (VWP) enables citizens of participating countries to travel to the U.S. for tourism, business or transiting the U.S. for 90 days or less without obtaining a U.S. visa as long as they meet certain conditions. For more information about the VWP and ESTA, and the requirements for these, please visit the website of the US Embassy in Dublin.
If you do not meet the requirements for the VWP you may need to apply for a US visa. For more information about US visas, please visit the website of the US Embassy in Dublin.