This is the name given to the area in the northern portion of the andes mountains that is the most extensive area of high plateau in the western hemisphere.

The correct answer is - Andean Plateau.

The Andean Plateau, also referred to as Altiplano, is located in the northern part of the Andean Mountain Range. It is spread out on the territories of the countries of Bolivia, Peru, Chile, and Argentina. This plateau, is the second largest high elevation plateau in the world, with its average elevation being 12,300 feet. The only bigger high elevation plateau in the world than the Andean Plateau is the Tibetan Plateau in Asia.