On one of Altan’s early visits to America in 1985, the first concert the band played was in the Blue Hill Town Hall before a crowd of a couple of hundred people.

They’d been invited to the area to perform at the old Rockport Folk Festival by George and Pat Fowler of Sedgwick, who, on a trip to Ireland in 1984, had met the band’s founders, Mairead Ni Mhaonaigh and her late husband, Frankie Kennedy.

“They arrived on the Fourth of July and we took them to a lobster feed on Little Deer Isle,” George Fowler said. “There are still people who come up to me and say, `Do you remember that night when we first heard Altan?’ It’s become sort of a legendary thing.”

Altan has built its own legend in the intervening years, becoming one of the pre-eminent performers of traditional Irish music and drawing crowds 10 times the size of that first audience in Blue Hill. Still, the performers have maintained their ties with the Fowlers and with the Hancock County area and have returned many times to perform.

Altan will return to The Grand Auditorium in Ellsworth for the St. Patrick’s Day weekend and will perform two concerts Sunday, March 19.

The band consists of Ni Mhaonaigh on vocals and fiddle; Ciaran Tourish on fiddle and whistle; Ciaran Curran playing bouzouki, a traditional Greek instrument (new but well-suited to Irish music); Dermot Byrne on accordion, and Daithi Sproule and Mark Kelly on guitar. Kennedy died of cancer in 1994.

The band performs as a tight-knit unit, though Ni Mhaonaigh, as lead singer, stands out. Her voice is as fresh and pure as the heart of Ireland itself; rock-solid on the often intricate traditional melodies, and yet as ethereal as the evening mists drifting down from Errigal Mountain toward Loch Altan, from which the band drew its name.

Altan is also known for its vigorous instrumental work. Their concerts are filled with jigs and reels marked by the Donegal style of fiddling of which Mhaonaigh and Tourish are acknowledged masters.

That style is marked by a lot of single-bowing, with more up and down on the bow and not quite as many notes played per bow stroke.

“It’s very accented and percussive,” said Fowler, himself a fiddler, who also promotes Celtic music as one of the hosts of “New Potatoes,” a regular radio program on WERU-FM in Orland. “There’s a lot of emphasis on the dance aspect of it. It’s not as subtle as some fiddle playing.”

And though the reels and jigs are robust and raucous enough to set every toe in the pub to tapping, some of the fiddle work can be poignant enough to move every heart to tears.

“The group has a sincerity and genuineness. They clearly love what they are doing,” Fowler said. “They have a great deal of energy when they play; they give their all.”

The band is more like a family than a band, he said, and there are no “swollen heads” in the group.

“Frankie said to me one time that `we don’t take ourselves very seriously, but we take our music seriously.’ There’s very little ego within the band when they perform. They enjoy people and are very generous with an audience, both during the concert and afterwards.”

Their concerts — and their CDs — are a mixture of vocals and instrumentals, including their latest release “Another Sky.” Most of the material is drawn from the deep traditional tunes of rural County Donegal in northwestern Ireland, which have been passed down through generations of singers and fiddlers.

“Gusty’s Frolicks,” one of the cuts from “Another Sky” was a fiddle tune Mhaonaigh learned from John Doherty, a legend in the Donegal style of fiddling. An itinerant tinker by trade, Doherty, according to the legend, never had a home or a fiddle of his own, but found both ready and waiting at every town.

“He was recorded in the early ’80s,” said Fowler, “He was unschooled, but he was a brilliant player.”

The group’s accordion player, Dermot Byrne, learned “Eoghainn O Ragadain,” another cut from the CD, from his uncle, Paddy, who heard it from a local singer who lived between 1832 and 1920.

“So you have a tradition running from 1832 down to the present,” Fowler said. “The music is closely rooted in personal stuff … They’re getting it right from the people in that area.”

Although Altan has remained true to those roots, the band has not hesitated to pick up tunes along the way. The new CD includes a pleasing rendition of Bob Dylan’s “Girl From the North Country” as well as a waltz they picked up here in Maine.

It was during that first visit to Maine, when Mhaonaigh heard Jeff Titon playing the “lovely tune,” which she later learned from Fowler. The tune, “The Oopik Waltz” (or Eskimo Waltz) stayed with her all these years and finally made its way onto a CD. Both Titon and Fowler are credited in the liner notes that accompany “Another Sky.”

“That’s the way Altan has been,” Fowler said. “They’ve always included the music around them.”

They’ll bring all that music to The Grand during concerts at 2 and 7 p.m. March 19. Tickets are $20 for adults in advance, $22 at the door and $10 for children under 17. The Grand Box Office is open from 10 a.m. to 4 p.m. Call 667-9500 for information.