A press release on the Asthmatic Kitty website reported that the Illinois album was supposed to be a double record (with somewhere near 50 songs), but the idea was eventually scrapped.

After the success of the album, Stevens returned to his digital 8-track recorder in late 2005 and began the process of finishing 21 of the previously abandoned songs, which would eventually become The Avalanche.

Stevens has stated during interviews that although he doesn't like The Avalanche as much as Illinois, he felt it was important to release the songs in light of the success of his most recent album.

The track "No Man's Land" plays during the closing credits to the 2006 film Little Miss Sunshine, which also features "Chicago" by Sufjan Stevens.

A Chevrolet Avalanche is featured on the cover, with an old-style Illinois License Plate which reads, "AKR 022", a reference to the catalog number of the album on Asthmatic Kitty Records.