This is one of those tours that make you wonder why no one has thought of pairing these two artists before. While Dar Williams and Joan Osborne both appeared on the inaugural Lilith Fair tour, the artists have never commanded a headlining tour together.

From her 1993 Razor & Tie debut, The Honesty Room, to reworking her own material for the 2010 double-disc anthology Many Great Companions, Williams has more than proven herself as an authentic American songwriter. She’s worked in the past with such Americana notables as John Prine and Lucy Kaplansky.

Osborne has carved out a very unique career since her first album, 1995’s Relish, debuted on Mercury Records. To the casual radio listener she’s the one behind the single “One Of Us” while avid concertgoers know her by her festival appearances and through tours with The Dead and The Funk Brothers.

The tour begins in Eugene, Ore., at McDonald Theatre Sept. 15. Other stops include Napa, Calif., at the Napa Valley Opera House Sept. 16; San Francisco at the Fillmore Auditorium Sept. 17; Los Angeles’ El Rey Theatre Sept. 19; Mesa, Ariz., at the Virginia G. Piper Repertory Theatre Sept. 20; Flagstaff, Ariz., at Orpheum Theater Sept. 21; Denver’s Gothic Theatre Sept. 24; Chicago at Park West Sept. 29 and Bloomington, Ind., at Buskirk-Chumley Theater Sept. 30.

Some shows are already on sale. Visit DarWilliams.com and JoanOsborne.com for more information.