Blind Willie McTell's blues are often considered as examples of the Piedmont blues. Here's a quote describing the Piedmont blues:

Piedmont blues refers to a regional substyle characteristic of African-American musicians of the Southeastern United States. Geographically, the Piedmont means the foothills of the Appalachians West of the tidewater region and Atlantic coastal plain stretching roughly from Richmond, VA, to Atlanta, GA. Musically, Piedmont blues describes the shared style of musicians from Georgia, the Carolinas, and Virginia as well as others from as far afield as Florida, West Virginia, Maryland, and Delaware. It refers to a wide assortment of aesthetic values, performance techniques, and shared repertoire rooted in common geographical, historical, and sociological circumstances; to put it more simply, Piedmont blues means a constellation of musical preferences typical of the Piedmont region. The Piedmont guitar style employs a complex fingerpicking method in which a regular, alternating-thumb bass pattern supports a melody on treble strings.  The guitar style is highly syncopated and connects closely with an earlier string-band tradition integrating ragtime, blues, and country dance songs. It's excellent party music with a full, rock-solid sound. ~ Barry Lee Pearson 
The quote is from All-Media Guide. 


As a commercial center and geographically favored recording location, Georgia drew a host of musicians offering many modes of playing, especially those of the technically sophisticated East Coast states and those of the Deep South who preferred a driving, emotive approach. The resulting mix offered an incredible array of styles. Atlanta musicians like Barbecue Bob may have favored 12-string instruments, but Georgia itself offered as many bottleneck guitarists as Mississippi. Intricate ragtime guitarists contrasted with musicians who often worked out of one cord; some, like Willie McTell, managed to encompass several different formats with equal vigor. 
The quote is from YaZoo Blues Mailorder.

**The background image is from The Roadmap to Great Music.