From Wikipedia, the free encyclopedia. Wilco is an American alternative rock band based in Chicago, Illinois. The band was formed in 1994 by the remaining members of alternative country group Uncle Tupelo following singer Jay Farrar's departure. Wilco's lineup has changed frequently, with only singer Jeff Tweedy and bassist John Stirratt remaining from the original incarnation. Since early 2004, the other current members are guitarist Nels Cline, multi-instrumentalists Pat Sansone and Mikael Jo ...