Here in New Orleans, most of the Irish-Americans (the "homegrown" ones, anyway), are many generations removed from Ireland. The effects on local Irish-American culture are obvious.

New Orleans was the most popular of all American ports of entry during the first wave of Famine-induced emigration, because jobs were available for the digging of the New Basin Canal. Many of the immigrants who took these jobs ~ mostly Irish, but other Europenas as well ~ lacked immunity to various tropical diseases, notably yellow fever, and died in huge numbers. Folks back home in Ireland knew only too well about this mortality rate (an Irishman actually had better statistical odds for survival staying home and enduring the Famine than digging the canal in New Orleans), so Irish immigration to this city soon came to a permanent halt. The upshot: longtime New Orleanians with Irish surnames and/or ancestry generally have no known relatives in Ireland any more, and most of their family trees reflect multiple generations in the American "melting pot" ~ as many Italian, French, German and other ancestors as Irish.

The musical/cultural upshot of this situation is a general indifference to "real" Irish traditional music, in favor of Bing-Crosby-esque Irish-American sentimentality. You don't even hear much in the way of rebel songs. There is a small community of musicians and fans with an interest in more authentic Irish music (including folks with closer connections to the home country), but they may be less visible during St. Paddy's Week than at other times of the year, because they're "drownded out" by the onslaught of faux-Irish celebration.

A notable exception is the fairly recent emergence of "The Lakes of Pontchartrain" as a popular performance piece for any local act pretending to any degree of Irishness. This song, of course, is unique in the trad-Irish repertoire for being set here in south Louisiana. While the lyrics make no specific reference to the New Basin Canal nor to the flood of Irish immigrants who came to this area to work on the canal, I privately suspect that the song's origins must have something to do with that historical event.