Most scientist agree that the Barberton Greenstone Belt in eastern Africa is the oldest mountain range on Earth (3.5 billion years old), and it is said that it is possible to deduce the entire geological history of the Earth by examining these uprising mountains in this ancient sea floor area. The Guiana Highlands in South America are thought to be the earth's oldest surface (2 billion years old): it includes a large mountain plateau. Then there is the Medicine Mountain on Wyoming were they have dated rocks to 2-3 billion years ago. However, on top of all this we have the 3.8 billion year old 25 mile long band of zircon crystal rocks embedded in the Isua crust in Greenland! (http://www.findarticles.com/p/articles/mi_m1134/is_4_113/ai_n6026419 A lot of people in the U.S. think that the Appalachians were among the oldest mountains formed. Although they are very impressive, stretching from the Eastern U.S. to Canada, Labrador, Scotland and down to Morocco, they were formed only about 680 mya during the formation of Pangaea. But we now know that Pannotia preceded Pangea and another supercontinent called Rodinia formed 1,100 mya. So if we have evidence of mountains at 3.8 bya, we must have had a land mass on Earth even way before then? This seems to contest the theory that the Earth was totally underwater until 3.8 bya, and that we still don't know?