The Kemp Family Singers are also mentioned in this article:

http://www.northatlanticbluesfestival.com/category/news/

…"Maine was first prominently mentioned in blues lyrics in 1928 when Mississippian Jimmie Rodgers recorded "The Brakeman's Blues," which contained the stanza "Portland, Maine, is just the same as sunny Tennessee; Any place I hang my hat is home, sweet, home to me." Blues probably reached Maine via traveling minstrel and vaudeville shows in the early decades of the twentieth century. African American minstrel troupes first visited after the Civil War, and Maine had its own Kemp Family Minstrel Show, founded in Leeds by George Washington Kemp, a former slave from Virginia. Because of Maine's remote location and small black population, however, few blues performers toured here until the music began to gain a solid foothold in the 1970s among white supporters, on the heels of the 1960s blues revival"…

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The exact same comment as given in the above excerpt is also found at http://www.msbluestrail.org/_webapp_3395447/Mississippi_to_Maine

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I really hope that GUEST,davlaudee who posted on 21 Jun 10 - 03:58 PM has followed up on her stated intention to do some genealogical research on this family. However, I've not found any genealogical research online of George Washington Kemp, African American (born in Virginia, lived in Maine).

There are, however, a number of genealogical pages and other websites about other men named George Washington Kemp. From the information given, those men were White.