From IslayInfo.com

Directions: From Port Ellen drive up the Oa and follow the road all the way to the end. At the t-junction keep left and follow the signposted track (RSPB Nature Reserve) to the parking place.

Start: Follow the track heading down to Upper Killeyan but keep right before the bend and follow the signs for the American Monument. The route up to the Monument is very well marked. Higher up the heathery terrain can be a bit wet and boggy in places. Just before you reach the momument there are dramatic views of the cliffs on your left. Around the monument are stunning views over the North Channel, the sea between Ireland and Islay. Up on the cliffs it can be very windy, warm clothes are recommended.

You can either return following the track where you came from or you can head east and complete the circular walk. This part of the route is also waymarked. As you walk along the top of the cliffs you have more stunning views of the Oa before you head back to the parking place while passing Upper Killeyan Farm. This walk is suitable for younger kids, aged 4+ but do not lose them out of sight, the winds can be tracherous and the cliffs are very high!

From IslayInfo.com:  The American Monument is built on a 429 foot (131 metres) high cliff on the Oa Peninsula in 1920 by the American Red Cross, and is designed by architect Robert Walker. The monument commemorates the loss of two troop ships in 1918, the Tuscania and the Otranto and the location overlooks the very spot where the Tuscania sunk. The monument is built in the shape of a lighthouse and is visible from many areas on Islay. A pleasant half hour meadow and moorland walk from the RSPB parking place takes one to the monument.

The Tuscania, a passenger liner, was on its way from New Jersey to the coast of France with 2,000 American soldiers and a crew of more than 300. At Halifax, Nova Scotia, they joined a convoy and entered the British waters between Islay and Northern Ireland on the 5th of February. The convoy was followed by a UB-77 German submarine which torpedoed the Tuscania. The direct hit on the Tuscania resulted in heavy damage and the Tuscania sunk after a few hours, 7 miles off the Islay coast near the Oa peninsula. An estimated 230 lives were lost in this tragedy.

Eight months later, on October 6 1918, another tragedy occurred only a few miles from the place where the Tuscania sunk. The HMS Otranto was carrying troops from New York to Glasgow when it collided with the steamship HMS Kashmir during a heavy storm. This tragedy took place not far from Machir bay on Islay's west coast. Over 400 lives were lost, both British crew members and US servicemen. A lot of victims were buried on the military cemetery at Kilchoman.

The monument itself has two plaques. A large one on the east side of the monument which looks like an entrance door, and a smaller one on the seaside in front of the monument.

Larger plaque:

Sacred to the immortal memory of those American Soldiers and Sailors who gave their lives for their country in the wrecks of the transports Tuscania (feb 5th 1918) and Otranto (October 6th 1918). The monument was erected by The American Red Cross near the spot where so many of the victims of the disasters sleep in everlasting peace.

On Fame's Eternal camping ground
Their silent tents are spread
While Glory keeps with solemn round
The bivouac of the dead

Smaller plaque:  A tribute from Woodrow Wilson, President of the United States of America. To the memory of his fellow citizens who gave their lives for their country in nearby waters, dated 1918.