People often ask me what the difference is between traditional country music and folk music, and my honest answer is "not a whole lot." Many of the songs the early folk musicologists were collecting have been as much an influence on the trajectory of country music as they have on that of what's sold as folk music. While commercial country music has taken a completely separate path, veering toward the aesthetic of pop music, there are plenty of people holding down the fort for traditional country (which sounds an awful lot like folk music to me).
Besides, folk and country have a number of common ancestors. Chief among them is the Carter Family - a trio of cousins whose music came to influence some of the strongest pioneers in recorded folk and country music - namely Johnny Cash and Woody Guthrie. If you're interested in the advent of story songs, topical songs, gospel-folk, and the like, chances are you'd enjoy learning a bit more about the Carter Family tree.
image: Carter Family promotional photo