American bluegrass musicians who took their Ozark Mountain style to California and helped lay the groundwork for country rock as well as for a “progressive” style of bluegrass music (bluegrass). The original members were Douglas Dillard (b. March 6, 1937, East St. Louis, Ill., U.S.), Rodney Dillard (b. May 18, 1942, East St. Louis), Mitchell Jayne (b. May 7, 1930, Hammond, Ind.), and Roy Dean Webb (b. March 28, 1937, Independence, Mo.). Significant later members were Paul York (b. June 4, 1941, Berkeley, Calif.), Byron Berline (b. July 6, 1944, Caldwell, Kan.), and Herb Pederson (b. April 27, 1944, Berkeley).

Banjoist Doug Dillard and guitarist Rodney Dillard found early success as performers in south-central Missouri before moving to California. There, against the backdrop of the folk music revival of the early 1960s, they issued three well-received albums that demonstrated their mastery of the rock idiom as well as their deep roots in traditional mountain music. Doug left the Dillards to pursue this country-rock fusion, eventually teaming with Gene Clark, formerly of the Byrds (Byrds, the), to form the pioneering country-rock band the Dillard and Clark Expedition. Meanwhile, Rodney took the Dillards in the direction of “progressive bluegrass,” adding drums, pedal steel guitar, and amplified instruments and featuring cover versions of material by contemporary songwriters such as Tim Hardin, Bob Dylan (Dylan, Bob), and the Beatles (Beatles, the). The Dillard brothers continued to be a presence in bluegrass and country rock into the 1980s.