Here they are, complete with room counts (which can fluctuate on a daily basis as suites get divided and recombined and rooms come in and out of service, so don't hold us to any of them exactly):
1. MGM Grand, 5,029 2. Luxor, 4,408 3. Mandalay Bay, 4,341 4. Venetian, 4,027 5. Excalibur, 4,008 6. Bellagio, 3,993 7. Circus Circus, 3,774 8. Flamingo, 3,565 9. Caesars Palace, 3,349 10. Palazzo, 3,066 11. Mirage, 3,044 12. Monte Carlo, 3,002 13. Las Vegas Hilton, 2,956 14. Paris Las Vegas, 2,916 15. Treasure Island, 2,885 16. Bally's, 2,814 17. Wynn Las Vegas, 2,716 18. Imperial Palace, 2,635 19. Harrah's, 2,579 20. Planet Hollywood, 2,567 21. Rio, 2,563 22. Stratosphere, 2,444 23. Riviera, 2,100 24. New York-New York, 2,035 25. Golden Nugget, 1,907
The nine of them that pre-existed the Mirage are: Circus Circus, Flamingo, Caesars, Hilton, Bally's, Imperial Palace, Harrah's, Golden Nugget, and Riviera. (Planet Hollywood predates the Mirage, though it was called the Aladdin and wasn't on the largest list until its reincarnation in 1999.)
Also note that only three other hotels in the entire U.S. would make this list: Hilton Hawaiian Village at 3,386, Gaylord Opryland at 2,881, and Disney Pop Century at 2,880.
