St. Patrick's Day is all about good music and festive gatherings. Here's a sampling:

* Celtic Celebration: Altan — 8 p.m. Thursday. Peter Norton Symphony Space, 2537 Broadway, Manhattan. Traditional Celtic quintet Altan celebrates its 25th anniversary with World Music Institute. $25, students with college ID $15. 212-864-5400 or worldmusicinstitute.org.

* The Chieftains – 3 p.m. Sunday. New Brunswick Cultural Center State Theatre, 15 Livingston Ave. This Grammy-winning band has been around since 1962. $32 to $62. 732-246-7469 or statetheatrenj.org.

* The Band of the Irish Guards & The Royal Regiment of Scotland – 8 p.m. Thursday. Community Theatre at Mayo Center for the Performing Arts, 100 South St., Morristown. The Band of the Irish Guards regularly performs for the mounting of the Queen's Guard at Buckingham Palace. $32 to $67. 973-539-8008 or mayoarts.org.

* Boys of the Lough – 4 p.m. March 21. Anna Maria Ciccone Theatre, Bergen Community College, 400 Paramus Road, Paramus. Keep the Celtic spirit alive with this Grammy-nominated ensemble, playing Irish and Scottish music. $20, students and seniors $18. 201-447-7428 or bergen.edu/cca.