Originating Location: US South/Appalachia
Originating Era: 1940
Bluegrass is a form of country music that came out of the Scots/Irish immigrants to Appalachia, which explains the similarities between bluegrass and other forms of country music to celtic music. Bluegrass is typically performed with many stringed instruments, especially mandolin and banjo rounding out the sound of guitars. There are often layers of vocals, but the main vocal is often a higher-pitched, nasal sound, sometimes with a bit of a dissonant-though-pleasing sound with the rest of the music. The O Brother Where Art Thou soundtrack helped bring bluegrass back to the public consciousness, though bluegrass never really went away; it was just continuing on as a bit of a cult-genre for a while, relatively ignored by mainstream country music, aside from its obvious influences on even pop-country.