1st, 350 yards, par four: A benign opening to Merion will see most players using an iron off the tee which is situated right beside the clubhouse patio. Playing to the corner of the dogleg should set up a wedge into the green, with a large sycamore tree on the right likely to dissuade the long hitters from cutting the corner and trying to drive the green.
2nd, 556 yards, par five: One of only two par fives on the course and probably the only one reachable in two. The fairway has been moved to the right to create a more daunting tee shot, with out of bounds looming closely on the right and heavy rough to the left. A relatively flat green offers birdie opportunities if trouble can be avoided on the way.
3rd, 256 yards, par three: The longest par three on the course, although a tee reducing the hole to 219 yards may also be used. The green slopes severely from back left to front right, meaning missing the green left will leave a fiendishly difficult pitch. A very deep bunker guards the front right of the green.
4th, 628 yards, par five: A new tee brings the fairway bunkers into play and the fairway itself slopes from right to left. Most players will lay up with their second shot to leave a short-iron approach to a green guarded by a creek and several bunkers.
5th, 504 yards, par four: A daunting drive awaits on the fifth, which doglegs from right to left and has a stream running down the entire left-hand side of the hole. The green slopes severely from right to left and a par here will be celebrated like a birdie.
6th, 487 yards, par four: Another long par four which features a semi-blind tee-shot into a bowl-shaped fairway. The second shot is played slightly uphill to a green with a false front that slopes from back to front.
7th, 360 yards, par four: The seventh begins a stretch of holes that could provide some welcome respite, although an iron off the tee will have to be accurate with out of bounds on the right. The green has three levels and anyone missing left will have a tough up and down from a severe slope.
8th, 359 yards, par four: Heavy rough on either side of the S-shaped landing area protects another short par four, with more deep rough and bunkers surrounding the small green. The tee may be moved up on one day to give players the option of trying to drive the green.
9th, 236 yards, par three: The front nine ends with a difficult par three played downhill to a kidney-shaped green. A water hazard guards the front of the green and deep bunkers mean the back-left pin position will be equally treacherous.
10th, 303 yards, par four: Only 47 yards longer than the par-three third, the 10th is a reachable par four that favours players who can draw the ball into the green. The more conservative play will require an iron off the tee to a narrow fairway.
11th, 367 yards, par four: After a blind tee shot, the players will see Baffling Brook which runs down the left-hand side of the fairway before curving round in front of the right side of the green. A good birdie chance if the approach is played from the fairway.
12th, 403 yards, par four: A dogleg right made more difficult by a fairway which also slopes from left to right. The green also slopes severely from back left to front right meaning any wayward approach will leave a tough up and down.
13th, 115 yards, par three: One of the shortest holes in modern major championship history, the 13th will nevertheless still provide some problems with a small, undulating green obscured by a large bunker in front of the putting surface.
14th, 464 yards, par four: A rare chance to hit driver off the tee, but danger lurks at the green with approach shots pulled left in danger of bouncing off a mound and running out of bounds.
15th, 411 yards, par four: Possibly the toughest drive on Merion's East Course, with a left to right dogleg guarded by out of bounds on the left and deep rough and bunkers to the right. A severely sloping green also awaits the approach shots.
16th, 430 yards, par four: Most players will attempt to lay up short of the quarry on the left to leave a medium iron to a green with a large depression in the front right corner. A possible birdie chance before the tough final two holes.
17th, 246 yards, par three: More than twice the length of the 13th, although a tee reducing the hole to 195 yards can also be used. A ridge across the front of the green makes an accurate approach difficult.
18th, 521 yards, par four: A par four measuring more than 500 yards, the 18th is likely to play the toughest hole of the week. The landing area at 300 yards runs downhill and from right to left, leaving longer hitters with a shorter approach played from a sidehill lie. The fairway plaque commemorates Ben Hogan's brilliant one-iron approach in the final round of the 1950 US Open which helped him into an 18-hole play-off which he won the following day.