On their recent fifth album, the ladies of Celtic Woman sing about New York's Ellis Island, celebrating the 17 million Irish who passed through on a quest for the American dream.

The group can relate: With virtually no attention in their homeland, the Irish quintet has become a cultural force in the United States, where a series of high-profile PBS specials has spawned five hit tours, albums and DVDs.

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<b>Celtic Woman</b>

8 p.m. Friday at Artpark, Lewiston.

Tickets are $35 to $49.50.

For info: www.artpark.net, www.tickets.com

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And no citizenship tests required.

"The demand here has been really huge, and we're really grateful for it," says Dublin's Chloe Agnew, who at 20 is the youngest member and one of three remaining from the group's 2005 debut. "This is like our home now. There's nowhere else we feel more at home. We've spent more time here the last few years than in Ireland."

This time the tour, stopping at Artpark on Friday, is in support of "Songs From the Heart," the group's fifth project. Agnew, Lisa Kelly and fiddling dynamo Mairead Nesbitt are now joined by singers Lynn Hilary and Alex Sharpe, who both became permanent members last year. And the 2010 show features some new twists, including several songs not found on record and a soaring "Amazing Grace" with award-winning bagpiper Anthony Byrne.

The good-natured, easy-on-the-eyes quintet is the latest in a long line of musicians who have found U.S. success via traditional Irish elements. By the time "Celtic Music" got its own tab in the racks at your local record shop in the '80s, the success of groups like Clannad and Altan had confirmed that Americans possessed a reliable sweet tooth for the rich, rousing sounds of the Emerald Isle.

"Irish music is so connected to our heritage and culture, where we come from," says Agnew, a buoyant and earnestpersonality whose enthusiasm practically pours through the phone. "You look back to our history: In the hardest times and the happiest times, Irish people turned to music. There are drinking songs. There are songs for milking the cow. Without a doubt it's in our blood."

But Celtic Woman brings a new spin to the party: Amid the uilleann pipes and ancient Gaelic tones is a big, glossy pop sensibility, where Sting covers and Disney songs sit side by side with centuries-old folk songs. It's Celtic music by way of globalization -- a recognition that the group operates in a music marketplace where Hollywood sizzle sells.

If that sounds a little like "Riverdance," it should: Celtic Woman was formed in 2004 by that show's musical director, David Downes, who astutely foresaw a market for Celtic music with a girl-group twist. The concept, explicitly designed and packaged for PBS, was an instant hit in '05, and the group's self-titled debut album spent more than a year atop Billboard's world music chart.

Celtic Woman is often described as Irish music in Spice Girls packaging. But a better analogy might be modern country music, with its pop-coated, personality-driven approach to a traditional music form.

"All the songs chosen for this show are songs that mean something to us," says Agnew. " 'Galway Bay,' which I sing in the show, is a song my mother, my grandmother, used to sing. I remember sitting on the carpet in front of the fireplace. People can feel that. It doesn't matter whether the music is in Gaelic or English, they take something away from it."

And Agnew quickly learned that the American fascination with Irish culture isn't just happenstance: At the tour meet-and-greets where fans proudly rattle off their genealogical stats -- a quarter Irish on this side, one-sixteenth on that one -- the young singer has gotten a primer on a unique branch of her own heritage.

"You look at America, and because there are so many people with Irish in them, coming out and listening to two hours of music connects them to their culture, to their ancestors," she says. "There are people at our shows who've never been to Ireland, and may never get there. But listening to us they can get a feeling of their history and feel it in their hearts."

Agnew, who will turn 21 in June, is looking ahead to a life that will likely include solo albums -- showcasing her own songwriting -- and possibly even a move to the United States. But for now her focus is on the Celtic Woman tour, which will keep the group on the road this year for 11 months, including runs through Asia and Australia.

And yes, says Agnew, anticipating the most common question the group members get: Despite the constant close quarters, they get along just great, onstage and off. That's all the more impressive considering that the three original members -- Agnew, Kelly and Nesbitt -- met just a couple of days before the first PBS special was taped.

"Wonderful, amazing friendships have been formed across the board here, and not just with the five of us, but with the whole band and crew," she says. "We're a little family, and that's why we can tour together 11 months out of the year. We've watched this show go from nothing to being this fantastic success. It's like watching a child grow, going from strength to strength, and it's been an amazing thing to be part of."