Although the state where Delano is located is never revealed, one might believe it is in South Carolina, since the shots of the inside of the State House, show palmetto trees in the lobby. The palmetto tree is the state tree of South Carolina.
It is interesting to note that Tyler's wife, Liz, is worried that he will be recognized in Delano, since he grew up there. Her fears are well founded, when Pieback Johnson, the town drunk, recognizes him, but no one makes anything of it. Later, when Tyler pulls over Hoss Spence, and Hoss attacks him with a cane, Tyler has flashbacks to when Hoss attacked him as a boy for spilling milk. However, Hoss should have recognized Tyler, and did not.
The trivia item below may give away important plot points.
The town Delano, in the book, I believe is Manchester, Georgia. The towns referred to on either side, are actual towns in that part of Georgia. Also, Franklin Delano Roosevelt had a house nearby, called The Little White House incidentally, where he died from a stroke. The name of the serial killer is Funderburk, which I believe is a name associated with that area. All these clues lead me to believe that Manchester, Georgia could be the town of Delano.