Altamont is from the playing of the African-American string band The John Lusk Band. It was first recorded in 1946. John Lusk was from Warren County, Tennessee, near McMinnville, and the band and their recordings have been well documented, as can be seen in this presentation by the Tennessee Folklore Society. The tune takes its name from Altamont, a town in Grundy County, Tennessee,  close to McMinnville.

David Bragger plays this tune in the key of C, and that is also the key of the original recording (below), as are most jam/festival versions. It appears that there are a couple of different versions of this tune, depending on who contributed the recording. The Rounder CD 0238 Altamont: Black Stringband Music from the Library of Congress  version of Altamont appears to be in the key of A. 

Whatever key you choose to play it in, it's a great tune. See more about David Bragger and his album, Big Fancy, in the Music Section.

David Bragger - Altamont