KingdomCon is held in San Diego, CA, USA. This year's dates are April 13th - 15th. This is the convention's third year.
Origin (Con) held in Columbus, Ohio, USA, one of the longer running and larger conventions in gaming.
GenCon held in Indianapolis, Indiana, USA, in August, also called GenCon Indy, this is definitely one of the classic conventions.
Kublah Con held in San Francisco, California, USA, occurs around Memorial Day Holiday, often features a game design contest.
Strategicon held in Los Angeles, California, USA near LAX (a maor LA airport), 3 times a year.
BGGcon "Open Board Gaming - Game Library with over 3500 games, plus the latest Essen releases."