The Lincoln Cent (or Lincoln Penny) was introduced in 1909, replacing the Indian Head cent. This was the first time that an American President appeared on any US coin. The Lincoln cent was designed by Victor D. Brenner, whose initials (VDB) appear prominently at the bottom on the reverse side of some of the coins minted that first year. Coins with these initials issued by the San Francisco mint are particularly rare, only 484 thousand having been produced. Later in 1909 the initials were discontinued, but reappeared again in 1918, this time on the obverse side, inconspicuously placed below Lincoln's shoulder.
From 1909 until 1958, the reverse side of the penny featured two sheaves of wheat framing the denomination and legend. Hence these pennies are known as "wheat cents." From 1959 until 2008, the design was changed to the Lincoln Memorial (1959 was the 150th Anniversary of Lincoln's birth). In well-preserved examples of these coins, Lincoln's statue may be seen within the monument. Lincoln is, thus, depicted twice on the coin - once on the obverse (the more obvious representation) and once on the reverse. The Memorial design was created by Frank Gasparro and his initials (FG) appear at the base of the Memorial on the right side.
In 2009, to mark the 200th anniversary of Lincoln's birth, the reverse was changed to four commemorative designs representing Lincoln's birth in Kentucky (log cabin), formative years in Indiana (rail splitter and law student), professional career in Illinois (Springfield State Capital), and Presidency (US Capital Building under construction).
The reverse was changed yet again in 2010 to a Union Shield designed by Lyndall Bass (initials LB to the left of the shield, below the denomination inscription).
Mint marks appear on the obverse side below the date. Mint marks are D for Denver and S for San Francisco. Coins minted in Philadelphia and all coins produced from 1965 through 1967 bear no mint mark.
The edge of the Lincoln Penny is plain (smooth). Until 1982, Lincoln Cents were composed of 95% copper (although in 1943, zinc-plated steel pennies were produced since copper was needed for World War II). In 1982, the composition was changed to zinc, clad with a small amount of copper (by that time the value of copper had risen to the point where the intrinsic value of the metal was worth more than the penny itself).