What is the absolute highest rank in the US Army?

You know that's not a rank, Commander and chief is a civilian rank given to the president as the head of the Executive of the 3 forms of our government.

Bryan, You said it... "It is a civilian rank"... which means that it is still a rank... and the Commander In Chief is the highest ranking official in the military... Any General or CSM or SMA is still outranked by POTUS...

Dude, you should know better than that. Washington did not want to be referred to by that title. That's not what he, the rest of the Founding Fathers, and the thousands of men who fought and died wanted, either.

There are few leaders in this or any country who lead us, but chose to walk away at the heights of his power. If that is not excellent what is? Only person that comes to mind is Cincinnatis of Rome, who Washington admired in history.

No

Technically, yes. General of the Armies of the United States is equivalent to a 6-star rank, although it was never implemented.

Never implemented... therefore doesn't exist.

General of the Army

General of the Army

As well as Washington, however you are right in that Pershing was the only living person to hold that rank.

No. General of the Army.

General Pershing also held that title. Washington's appointment was a posthumous one made by President Ford in 1976. The President said that this was being done so that Washington would rank first among all other officers of the Army, past and present.

Technically, LTC, Pershing's rank is only equivalent to a 6 star. Following WW2 there were talks to implement 6 stars, officially. As it stands now, the rank is 4 gold stars.

General of the Army (5 stars)

No. You're thinking of Eisenhower, who was named Supreme Allied Commander of the Allied Expeditionary Forces during World War 2.