IAH has the nation's highest fares

I thought so and now it is confirmed.

Topping the list is George Bush Intercontinental Airport in Houston, where passengers paid a premium of $85 — about 24 percent — on the average round-trip coach ticket. (Flights to Houston’s older, smaller field, William P. Hobby Airport, were only $8 overpriced).

United/Continental owns IAH so it's no surprise. IAH needs competition badly.