Appalachian Mountains

The  **Appalachian Mountains** (French: les Appalaches) are a large group of North American mountains. They are partly in Canada but mostly in the United States. They stretch  southwestward from the Island of Newfoundland, in Canada, to central Alabama, in the United States.
The individual mountains have an average height if around 3,000 ft (900 m). The highest is Mount Mitchel,l in North Carolina (6,684 ft or 2,037 m), which is also the highest point in the United States east of the Mississippi River and is the highest point in eastern North America.

The Appalachians are a barrier to east–west travel. Ridgelines and valleys run north–south, and travelers must climb them again and again. Only a few mountain passes run east–west. The Erie Canal was built through one of them. In most places, the Appalachians are the watershed between the drainage basins of the Mississippi River and the Atlantic Ocean.

The term **Appalachia** is used to refer to the mountain range and the hills and the plateau region around it. The term is often used to refer to areas in the central and the southern but not the northern Appalachian Mountains. Those areas usually include all of West Virginia and parts of the states of Kentucky, Tennessee, Virginia, and North Carolina and sometimes extend as far south as northern Georgia and western South Carolina, as far north as Pennsylvania, and as far west as southeastern Ohio. In 1965, the United States Congress created an Appalachian Regional Commission to include these areas and morem as far west as Mississippi.

The Appalachian Trail in the US is about 3,500 km (2,190 miles) long and goes through 14 states, from Georgia to Maine.

## Geologic history

The geologic processes that led to the formation of the Appalachian Mountains started 1.1 billion years ago. The first mountain range in the region was created when the continents of Laurentia and Amazonia collided and created a supercontinent called Rodinia. The collision of those continents caused the rocks to be folded and faulted, which created the first mountains in the region.

Over time, thesmountains were eroded by wind and water. The rocks that were eroded were deposited in the ocean, where they were eventually buried and turned into sedimentary rocks. Thesedimentary rocks were then uplifted and folded again, which created new mountains.

This process of erosion and mountain building has repeated itself many times over the past 1.1 billion years. As a result, the Appalachian Mountains are not a single continuous mountain range. Instead, they are a patchwork of different mountain ranges that have been created at different times.

The youngest rocks in the Appalachian Mountains are only about 250 million years old. The rocks were formed during the Alleghanian orogeny, which was the last major period of mountain building in the region.

The Appalachian Mountains are still being eroded. Over time, the mountains will continue to wear down, and the rocks that make up the mountains will eventually be recycled back into the Earth's crust.

In short, the geologic processes that led to the formation of the Appalachian Mountains started 1.1 billion years ago, but the mountains themselves are much younger. The rocks that make up the mountains are the result of millions of years of erosion, deposition, and mountain building.