The tournament runs Wednesday through Sunday, featuring 12 American players against 12 from anywhere else in the world, except Europe. The Americans play the Europeans in The Ryder Cup.
The American team includes Tiger Woods, Phil Mickelson, Steve Stricker, Zach Johnson, Stewart Cink, Sean O'Hair, Jim Furyk, Anthony Kim, Justin Leonard, Lucas Glover and Hunter Mahan.
"As of today, we are sold out Thursday, Friday, Saturday, and Sunday," said Tom Clark with The Presidents Cup. "We've got tickets available for tomorrow, Tuesday and Wednesday, which are practice rounds."
San Francisco is only the second U.S. city to host the tournament. At least one president, current or former, could make an appearance.
"President Obama has been invited, we're still waiting to hear if he's going to attend at all," said Clark. "There's a good possibility that President Clinton would be here and also President Bush."
The press center is set up to accommodate 450 media outlets from around the world.
There are 1,300 volunteers working the event, among them Sacramento Superior Court Judge Ken Peterson.
"They advertise very nicely for that, and they say that anybody that wants to volunteer you can, and I went online and there was an opportunity for about 13 different volunteer positions. They ask you to do your top three choices. I was fortunate to get my top choice," he said.
Using volunteers saves money for this tournament where all the proceeds are donated to charity.
"It's a feel good thing for us as volunteers to know that we're helping somebody out. It's also nice to be close to the action, to see who is doing well," said Peterson. "You know that the 24 people here are the 24 best golfers in the world, so you're seeing some real special people."
"The players don't get paid for this, there's no purse," said Clark. "They're here to play for the love of golf and the development of golf internationally, so all of the net proceeds go to charity,"
Roads around Harding Park will be closed during the tournament, so leave extra time if you need to drive in the area.
For more information on The Presidents Cup, including ticket information, visit www.pgatour.com/tournaments/presidentscup