by 1886 in American English in reference to a type of hound bred in the South, with a red or red and tan coat, used especially to hunt raccoons and fugitives. The name probably has some connection to the term Redbone as used in 19c. southern U.S. to denote a mulatto or mixed-race culture.
The Redbone is one of the old-time strains; confined exclusively to the Southern States. The "native" Birdsong, Georgia, Virginia, and Kentucky Hounds were undoubtedly the Redbone strain before the introduction of the various crosses previously mentioned. They were a slow, painstaking Hound, with superior nose and splendid mouth, without speed. [Gen. Roger D. Williams, "The American Foxhound," in "Dogs," New York: 1907]