The U.S. introduced the peanut to the tropical South America , and India , China , West Africa , and itself to become the largest commercial producers of peanuts . The peanut was grown mainly for its edible oil , except in the U.S. , where it was produced for grinding into peanut butter , for roasted , salted nuts ; and for use in candy and bakery products . Popular confections made from peanuts include salted peanuts , peanut butter ( sandwiches , peanut candy bars , peanut butter cookies , and cups ) , peanut brittle , and shelled nuts ( plain\/roasted ) .