Immigration Q&A: Is Irish citizenship possible for my second wife?
Americans do not need visas to enter Ireland. They can be granted stays of up to three months at a time.
If you’re looking to remain longer, it’s possible for the spouse of an Irish citizen to obtain a visa for long-term residence. For information, visit the Irish government’s Naturalization and Immigration Service website at http://www.inis.gov.ie/en/INIS/Pages/WP09000003.