“Katy Daley” (also “Come Down the Mountain Katie Daly”) is a traditional Irish folk song that crossed into the American bluegrass repertoire in the early 1960s. The earliest commercial recording with the modern title was made by the Irish singer Eamon O’Shea (real name Herman Weight) in November 1961 on the Dublin-based Glenside label. O’Shea’s version registered the song under his writer credit, although the song itself appears to have been a traditional Irish piece older than the 1961 recording.
The bluegrass adoption came almost immediately. Around 1961–1962, the Bluegrass Playboys (featuring former Clinch Mountain Boys member Paul “Moon” Mullins) cut a version on the Briar label, and Billboard reported in December 1962 that an “old Irish folk song done up in fine style” titled “Come On Down the Mountain Katie Daly” had become a bluegrass favorite. The credit was retained for Eamon O’Shea even as the song crossed the Atlantic.
The pivotal bluegrass recording was Ralph Stanley’s, on his 1971 album Something Old, Something New, and Some of Katy’s Mountain Dew. Stanley’s reading became the canonical bluegrass version that subsequent acts have referenced. The song has been carried forward by Tony Rice, Billy Strings, and many other contemporary bluegrass players, and it remains a regular jam-session call-out where pickers want a piece with strong Irish-bluegrass crossover character.