Refers to all the acoustic, guitar-driven, forms of the blues.

The traditional form of rural or country blues emerged in the 1920s as the recording industry grew, with performers such as Charley Patton, Blind Lemon Jefferson, Son House and Blind Blake becoming popular in the African American community. Country blues performers often improvised, either without accompaniment or with only a banjo or guitar.

There were many regional styles of country blues in the early 20th century.

The (Mississippi) Delta blues was a rootsy sparse style with passionate vocals. Blind Lemon Jefferson was one of the few country blues performers to record widely and may have been the first to record the slide guitar style, which became an important part of the Delta blues. Robert Johnson, who was little-recorded, combined elements of both urban and rural blues. Along with Johnson, influential performers of this style were his predecessors Patton and Son House.

Singers such as Blind Willie McTell and Blind Boy Fuller performed in the southeastern more lyrical Piedmont blues tradition, which used an elaborate fingerpicking guitar technique.

The lively Memphis blues style, which developed in the 1920s and 1930s around Memphis, Tennessee, was influenced by jug bands, such as the Memphis Jug Band and Gus Cannon's Jug Stompers. Performers such as Sleepy John Estes and Memphis Minnie used a variety of unusual instruments such as washboard, fiddle, kazoo or mandolin. Memphis Minnie was famous for her virtuoso guitar style. Pianist Memphis Slim began his career in Memphis, but his quite distinct style was smoother and contained some swing elements.

Many blues musicians based in Memphis moved to Chicago in the late 1930s or early 1940s and became part of the urban blues movement which blended country music and electric blues.