India, covering 1,269,338 square miles (3,287,590 square kilometers), is roughly one-third the size of the United States. The Himalaya Mountains, the tallest mountain system in the world, are located on India's northern border. South of the Himalayas, the fertile Ganges Plain is India's most densely populated region. The Great Indian (Thar) Desert extends westward from the plain into Pakistan. The Deccan Plateau in the south lies between the Western Ghats and Eastern Ghats, hill regions along the coasts of peninsular India. About half of the country is under cultivation and less than one-fourth is forested.