The Sisters Folk Festival organization recently announced it received a grant from the Oregon Cultural Trust for its 2018 summer concert series in Fir Street Park, which concludes Thursday with traditional Irish band Altan. Lead vocalist and fiddler Mairéad Ní Mhaonaigh and her husband, flutist Frankie Kennedy, founded the band in 1987, taking the name from a lake behind Errigal Mountain in their native Donegal (also the title of their second duo album together). The band continued to grow through the late ’80s and early ’90s, bringing the little-heard traditional music of Donegal to the U.S., Europe and beyond. Though Kennedy died of cancer in 1994, Ní Mhaonaigh and the band persevered, signing to Virgin Records in 1996. The band continues to tour and release albums including this year’s “The Gap of Dreams,” a showcase for Ní Mhaonaigh’s angelic voice and the group’s double-fiddle attack.

Altan: 6:30 p.m. Thursday; free; Fir Street Park, Fir Street and Main Avenue, Sisters; sistersfolkfestival.org or 541-549-4979.