Yes, bluegrass music is rooted in a form of Irish music (and Scottish).
Western North Carolina has long been fertile ground for the growth of bluegrass music. In fact, no other region or state has contributed so much to its development.
For many people, the appeal of bluegrass music is that it is a relatively new form of music that sounds old. Most scholars agree that bluegrass first gained national attention when Bill Monroe and the Bluegrass Boys appeared on the Grand Ole Opry in 1945. In addition to Bill Monroe himself, this legendary band consisted of Lester Flatt (guitar), Earl Scruggs (banjo), Chubby Wise (fiddle) and Cedric Rainwater (bass). The reason that bluegrass music sounds old is that it is a syntheses of many older styles of music.
The earliest settlers in western North Carolina were the Scotts-Irish. These early pioneers brought with them a wealth of both vocal and instrumental music traditions.
It was mainly the pioneer women who carried on the strong vocal traditions. Often barred by local custom from playing the more raucous instruments like the banjo or the fiddle, most women preferred to sing. More often than not, they sang the old ballads that had been passed down from mother to daughter for generations. Most of these ballads originated in the British Isles. They were carefully preserved by a culture that was bent on keeping in tact the cultural traditions of their ancestors. They preserved these ancient ballads so well, in fact, that during the years 1916-1918 English folksong collector Cecil Sharp came to western North Carolina for the sole purpose of collecting English ballads in their purest form, because in England these ballads had long been forgotten.
Ballad singing in western North Carolina had a strong impact on what later became known as bluegrass music. The subject matter of most of the ballads was either murder or death. This leant a somber tone to the music. Today, this is referred to as Bluegrass musicâ??s "high lonesome sound." The manner in which the old ballads were sung also affected the singing styles of later bluegrass singers. The women who sang the old Scotts-Irish and English ballads normally sang with a tight voice that produced a high, shrill tone. In contrast, singers from African traditions sang with a looser voice that produced lower and more relaxed tones. Bill Monroe, who later became known as "The father of Bluegrass Music," is the perfect example of someone who sang with the tight vocal style of his Scotts-Irish ancestors. In his case, he was able to emulate the vocal styles of female ballad singers because he naturally had a high vocal range similar to many female singers.