The Lincoln penny is a one-cent coin produced by the United States Mint, first issued in 1909. It features a portrait of Abraham Lincoln, the 16th President of the United States, on the obverse side. The reverse side originally depicted the wheat ears, symbolizing agriculture, until it was changed to the Lincoln Memorial design in 1959. Made primarily of copper and later zinc, the Lincoln penny has undergone various design changes over the years. It is widely collected by numismatists and is often used in everyday transactions. The coin remains a significant part of American currency and history.