The hornpipe probably has an Irish provenance, with first publication date around 1847. The melody has been adopted by several genres. For example, it was the basis for the old-time tune Possum up the Gum Stump.
Ref: https://tunearch.org/wiki/Annotation:Off_to_California_(1)
Ref: https://thesession.org/tunes/30
G | D | G | C | ||
G | C | Am | D | ||
G | D | G | C | ||
G | C | A | G | ||
Em | D | Em | Bm | ||
Em | D | C | Bm | ||
Em | Bm | Em | D | ||
G | G | D | G |