Bowker, a long-standing source of book publishing information declares in an article entitled "New York and London Are Most Popular Settings for Novels" also considers state locales. An extract states
"In addition to London, the other non-U.S. city to make the top 10 fictional settings was Rome. California was the setting for more novels than any other state, followed by Texas, Florida, Virginia, and North Carolina."
Texas novelists take note!