Mary Mack is a Scottish folk song, and is also a patter song, often sung not only with a rapid to very rapid tempo but increasing toward the end.
The definitive version of Mary Mack is, perhaps, the live version on the 1977 double album "Makem & Clancy Concert," performed live at National Stadium Dublin by the late great Irish troubadours, Tommy Makem and Liam Clancy.
"Mary Mac" has long been a fixture of Richmond, Virginia band Carbon Leaf's live sets.
A studio recording appears on their 2001 album Echo Echo and a live recording on their 2003 album 5 Alive!.
Another recording was done by Great Big Sea on their 1995 album Up, which is well-known throughout Canada.