So much is brand new about America's oldest golf championship.

Not to worry. The U.S. Open hasn't lost its reputation as the toughest test in golf. And it's still the most democratic of the majors, with more than half the field — including a pair of two-time champions — having to go through qualifying.

Just about everything else at the 115th U.S. Open is breaking new ground, starting with where it is being played.

Chambers Bay, a public course perched along Puget Sound south of Seattle, for more than a century was a sand and gravel pit used for mining. Ten years ago, it was still being built. And now it's the first U.S. Open in the Pacific Northwest, and the first major in the area since Vijay Singh won the PGA Championship in 1998 at Sahalee. No other golf course has been awarded a U.S. Open so soon after it opened.

Also new this year: Fox Sports was awarded a 12-year contract that starts this year. Johnny Miller no longer will be calling the shots. That now falls to Greg Norman. And Fox will be making its debut in major championship golf with a course hardly anyone has seen.

It's more than location that makes it so different.

Instead of thick rough typical of a U.S. Open, Chambers Bay has fine fescue grass that allows the ball to bounce and roll, similar to a links course. There are no tree-lined fairways because there is only one tree on the golf course.

"It's everything like a British Open," Phil Mickelson said after playing the Robert Trent Jones Jr. design. "I've never seen this type of fescue in the United States. I've never seen greens with fescue grass in the United States. The ball runs like the British. You're hitting the same shots as the British."

Maybe that bodes well for Mickelson, who hasn't won a tournament since the 2013 British Open. This is his second shot at trying to become only the sixth player with the career Grand Slam. All he has from the U.S. Open, the only major he has never won, is a record six silver medals.

The par 70, but even that is different. The USGA plans to move the tees and alternate par between 4 and 5 on the first and 18th holes. And there's a par 3 (No. 9) that has two sets of tees — one that makes it play slightly uphill, the other has a 100-foot drop to the green.

Players already are suspicious, especially after USGA executive director Mike Davis said that anyone who plays only two practice rounds and has his caddie walk the course to get the yardage off the tee and to the green is "done."

It's not clear if the USGA is trying to identify the best player or the best student of architecture.

"There's going to be someone lifting the trophy at the end of the week," said Rory McIlroy, the world's No. 1 player. "It's a bit of an unknown to most people, so you have to prepare. But you can fall into the trap of trying to over prepare."

He said that right before he missed consecutive cuts in Europe, his final competition before the second major of the year. Missing cuts is nothing new for McIlroy, but no less startling for the world's No. 1 player who has made mini-slumps in the summer two of the last three years.

Still, nothing is more surprising these days than Tiger Woods.

The last time the four-time champion played in the U.S. Open, at Merion in 2013, he was No. 1 in the world and in the midst of a five-win season. Now he is No. 181 and has gone nearly two victory since his last victory. Woods took two months off early in the year when his game hit an all-time low — an 82 in the Phoenix Open — and then three tournaments into his return, he shot an 85 at the Memorial.

Woods also took a reconnaissance trip to Chambers Bay and was struck by how different it could play, with a variety of tees that could allow some par 4s to be reached off the tee, and other par 4s that required a fairway metal for the second shot.

"What combinations is Mike going to present us?" Woods said. "He could make it to where it's just brutal, or he can make it to where it's pretty easy and give us a combination of both and then switch it up on every other hole. That's going to be the interesting part."

McIlroy and Masters champion Jordan Spieth are the betting favorites, and the form is with Spieth. Only three times in his last 10 events has Spieth finished out of the top 3, including a 65 at the Memorial in his final start. The 21-year-old Texan also has the advantage of being one of the few to have competed at Chambers Bay, although it may be a bad memory.

It hosted the 2010 U.S. Amateur, which it played bone dry and was much more unpredictable than it is now. Spieth was among 11 players at the U.S. Amateur who are back at the U.S. Open.

Spieth shot 83 and failed to advance to match play, though he wasn't alone. Brooks Koepka shot 81. Russell Henley shot 82.

"I didn't really see much of it," Spieth said. "Actually, I saw a lot of it — I didn't see much of the places I want to see."

This is a mystery that the world's best will have four days to solve.