“Molly and Tenbrooks” (also known as “The Race Horse Song”) is a traditional American song commemorating the July 4, 1878, match race at the Louisville Jockey Club (now Churchill Downs) between the Kentucky horse Ten Broeck and the California mare Mollie McCarty. An estimated 30,000 spectators witnessed the race, and the song appears to have been composed shortly afterward, most likely by Black stable workers in the 1880s who were closest to the horses.
The first known commercial recording was made in 1929 by the Carver Boys under the title “Tim Brook.” The song’s pivotal bluegrass moment came when Bill Monroe and his Blue Grass Boys recorded their version on October 28, 1947, with the canonical Columbia Records lineup of Lester Flatt, Earl Scruggs, Chubby Wise, and Howard Watts. The recording was held back and not released until 1949, paired with “I’m Going Back to Old Kentucky” on the same 78 release.
“Molly and Tenbrooks” is widely cited as the song that established bluegrass as a distinct genre. The Stanley Brothers’ 1948 cover — recorded explicitly in the Blue Grass Boys’ style — was the first time another commercial act consciously adopted Monroe’s bluegrass arrangement, and many historians treat that 1948 cover as the moment when bluegrass crossed from being one band’s sound into a recognized genre. The song remains a cornerstone of the bluegrass repertoire.
