The location of the mint mark on a Jefferson nickel is not fixed; its position has changed several times since the coin was first introduced in 1938. The specific year of the nickel is therefore the determining factor for locating the mark.
For nickels minted from 1938 to 1964, the mint mark can be found on the reverse side of the coin, to the right of Monticello. A significant exception occurred during World War II, from 1942 to 1945. For these "war nickels," which were composed of a silver alloy, a large mint mark (P, D, or S) was prominently placed on the reverse, directly above the dome of Monticello. This period marked the first instance of a 'P' mint mark, for the Philadelphia Mint, appearing on a United States coin.
Following this era, from 1965 to 1967, no mint marks were used on nickels.
Beginning in 1968, the mint mark was moved to the obverse, or "heads" side, of the coin. From 1968 until 2004, the mint mark is located to the right of Jefferson's portrait, near the date. It is worth noting that the 'P' mint mark for Philadelphia was not used again until 1980; nickels minted in Philadelphia between 1968 and 1979 do not bear a mint mark.
From 2005 to the present, coinciding with the Westward Journey nickel series and subsequent designs, the mint mark's location was slightly adjusted but remains on the obverse. It can now be found just below the four-digit date on the lower right side of the coin.
