The following list shows info on the U.S. Championship from Wikipedia. I've added venue and, where the event was a zonal, the subsequent FIDE event. The number in the first column is the series number of the U.S. Championship.
- 38 1992 Durango Wolff, Patrick -> 1993 Biel IZ
- 39 1993 Long Beach Shabalov, Alexander; Yermolinsky, Alex
- 40 1994 Key West Gulko, Boris -> 1997 Groningen KO
- 41 1995 Modesto de Firmian, Nick; Wolff, Patrick; Ivanov, Alexander
- 42 1996 Parsippany Yermolinsky, Alex
- 43 1997 Chandler Benjamin, Joel
- 44 1998 Denver de Firmian, Nick -> 1999 Las Vegas KO
- 45 1999 Salt Lake Gulko, Boris -> 2000 New Delhi KO
- 46 2000 Seattle Benjamin, Joel; Shabalov, Alexander; Seirawan, Yasser -> 2001 Moscow KO
- 47 2002 Seattle Christiansen, Larry
- 48 2003 Seattle Shabalov, Alexander -> 2004 Tripoli KO
For the 2004 Tripoli KO, all USA players qualified from the 2003 Continental Championship, Buenos Aires. All of the preceding KOs were World Championship events, although 1997 Groningen gets an asterisk ('*'), since reigning FIDE champion Karpov was seeded directly into the final round which was played after a short delay at another venue.
I didn't have time to double check the following, but I believe the U.S. Championship in odd years qualified to the corresponding Khanty-Mansiysk KO of that year, which were World Cup qualifiers to a subsequent event.
- 49 2005 La Jolla Nakamura, Hikaru; Tournament ('was played in 2004, but called the 2005 Championship, for legal reasons')
- 50 2006 San Diego Onischuk, Alexander
- 51 2007 Stillwater Shabalov, Alexander
- 52 2008 Tulsa Shulman, Yury
- 53 2009 St. Louis Nakamura, Hikaru
- 54 2010 St. Louis Kamsky, Gata
- 55 2011 St. Louis ?
I'll update my page on the World Chess Championship Zonals as soon as I can.
Later: After GM Shabalov, the 2003 U.S. Champion, informed me that the 2003 event was indeed a zonal, I reviewed my work and corrected my records. Apologies for the error.