Valley vs Canyon
If a river is flowing through a mountain, in due course of time, it carves out a deep area for itself to flow. This deep depression between two cliffs of a mountain is referred to as a canyon. It is also called a deep valley carved out of a mountain by a river. In case of both a valley and a canyon, a deep depression is made in a mountain that goes down to the bottom of the mountain with a U or V shape being formed on with steep sides of the mountain on either side of valley and canyon. Because of their similarities, it is hard to differentiate between these two landforms. This article attempts to highlight the features of a canyon as well as a valley to enable readers to understand their differences.
Both canyons and valleys look like deep grooves in the ground surrounded by mountains or cliffs on either sides. In effect, canyons are nothing but deep valleys made by the action of water with steep slopes on either side while valleys are lowland areas between two mountains and have gentler slopes than canyons. Another point of differentiation lies in the fact that valleys can be either small (a few hundred square miles in area) or very large (thousands of square miles in are) whereas canyons are smaller in size than valleys though they are also always deeper than valleys.
A valley is very wide with mountains on both sides and is characterized with a lot of vegetation. Geologists accept that canyon is a special type of valley and is a term used more often in US than in other parts of the world. It is derived from a Spanish word meaning a tube.
If you find it hard to differentiate, just think of Grand Canyon as you can easily visualize it. Valley is a generic term that applies to any depression between two cliffs or mountains. It usually contains a river. Indus Valley in Pakistan or Kashmir Valley in India is two very famous examples of valleys in the world. Just remember that a canyon is in essence a type of valley which is deeper and has steep slopes on either sides that are mountains or cliffs while valleys are general and described as a depression in a mountain with wide lowland area with gentler slopes and a lot of vegetation.