12 of the Rarest U.S. Mint Error Coins Worth a Fortune

Some of the rarest and most valuable coins in U.S. history owe their worth to minting errors that slipped through unnoticed. Coins like the 1943 Copper Penny, struck in copper instead of wartime steel, or the 1955 Doubled Die Penny, with a striking double image, are worth thousands — or even millions — due to these unique flaws.

We found several rare slip-ups in the minting process that are coveted by collectors. Here’s a look at some of these highly sought-after coins and what makes them so valuable.

1. 1943 Copper Penny

Estimated value: $1.7 million

The 1943 Copper Penny is a rare and highly valuable coin due to a minting error made during World War II. In 1943, the U.S. Mint was supposed to produce pennies using zinc-coated steel to conserve copper for the war effort. However, a small number of copper planchets (the metal discs used to make coins) were mistakenly left in the presses, resulting in a few pennies being struck in copper rather than steel. This rare oversight created one of the most sought-after coins of all time. With only about a dozen known to exist, the 1943 Copper Penny’s rarity drives its high value.

2. 1955 Doubled Die Penny

Estimated value: $125,000+

The 1955 Doubled Die Penny is a valuable and highly coveted coin among collectors due to a striking error that led to a unique doubling effect on the design. During the minting process, a misalignment caused the die to imprint the lettering and date twice on the coin, creating a noticeable “double image” that makes this penny stand out. The words “Liberty” and “In God We Trust,” along with the date “1955,” show the doubled effect most prominently, making it easily recognizable. This mistake created fewer than 24,000 coins, adding to the rarity and demand. 

3. 1975 No ‘S’ Proof Dime

Estimated value: $450,000

One of the rarest and most valuable modern U.S. coins is the 1975 No “S” dime, known for a rare minting error that left off the “S” mintmark. Normally, all proof dimes produced at the San Francisco Mint bear an “S” mintmark, signifying their origin. However, in 1975, a few proof dimes were mistakenly struck without this mark. Only two examples of this rare coin are known to exist, making it a prized possession for coin collectors.

4. 1937-D Three-Legged Buffalo Nickel

Estimated value: $100,000

Any three-legged animal causes a stir, and the 1937-D Three-Legged Buffalo nickel is proof (get it?). This unique coin was struck at the Denver Mint, where an over-polished die accidentally removed part of the buffalo’s front right leg, leaving it with only three visible legs. The mistake created a distinct and easily recognizable error that sparked the interest of collectors soon after its release. As a result, the 1937-D Three-Legged Buffalo Nickel has achieved legendary status, and its scarcity and novelty make it highly desirable. 

5. 1922 ‘No D’ Penny

Estimated value: Up to $19,000

The 1922 “No D” Penny is a rare and sought-after error coin from the Denver Mint, famous for its missing mintmark. In 1922, the Denver Mint was the only facility producing Lincoln cents, so all pennies from that year were supposed to bear a “D” mintmark. However, due to extreme die wear and over-polishing, some coins were accidentally struck without the “D.” The rarity and unusual history behind this error coin make it highly valuable among collectors, with well-preserved examples being particularly sought-after (especially because of the coin’s age).

6. 2004 Wisconsin Quarter Extra Leaf Error

Estimated value: Up to $3,000

Part of the U.S. Mint’s State Quarters program, the 2004 Wisconsin quarter was issued to celebrate the state’s heritage and features an image of a cow, cheese, and an ear of corn. However, some of these quarters were struck with an unusual die flaw that resulted in an “extra leaf” appearing on the left side of the corn stalk — either as a high or low leaf variation. The origin of this error remains debated, with some suggesting it may have been an intentional addition by a mint worker. Regardless, the two variations (high leaf and low leaf) are both rare, making these coins highly collectible and valuable. 

7. 1974 Aluminum Lincoln Cent

Estimated value: Between $250,000 and $2 million

The 1974 Aluminum Lincoln Cent is an elusive and highly valuable coin, notable for its unique composition. In 1974, the U.S. Mint experimented with producing pennies from aluminum rather than the usual copper to reduce minting costs amid rising copper prices. Around 1.5 million aluminum cents were struck and distributed to members of Congress for evaluation, but the proposal was ultimately rejected due to concerns about durability and compatibility with vending machines. Although most aluminum cents were melted down, a few escaped into circulation, making them incredibly rare. Today, the 1974 Aluminum Lincoln Cent is illegal to own privately, as the U.S. Mint considers it government property — though a few examples remain in private hands. 

8. 2000 Sacagawea Dollar Wounded Eagle

r/Brother-Orange via Reddit.com

Estimated value: Up to $5,000

The 2000 Sacagawea Dollar “Wounded Eagle” is a rare and intriguing error coin from the first year of the Sacagawea Dollar series. This error occurs on a small number of coins where an engraving flaw appears as a raised line or “gash” across the chest of the eagle on the reverse side, giving the impression of a wounded eagle. The error likely resulted from a die gouge, creating a distinct line that collectors now call the “Wounded Eagle” variety. 

9. 1942/1 Overdate Mercury Dime

Estimated value: $120,000

The 1942/1 Overdate Mercury Dime is a famous and valuable coin error cherished by collectors. This overdate error, found on dimes produced at both the Philadelphia and Denver Mints, occurred when the date on the die was changed from 1941 to 1942, but remnants of the original “1” were not fully removed before the “2” was stamped over it. As a result, the coin shows a visible overlapping of the “1” and “2,” creating a distinctive “1942/1” date. The error was caught after some coins were already struck, which made it relatively scarce. 

10. 1992 Close AM Lincoln Cent

Estimated value: Up to $5,000

Among Lincoln cents, the 1992 Close AM variety stands out as a rare and valuable error from the Philadelphia and Denver Mints. This coin features a subtle but important difference on the reverse: the letters “A” and “M” in “AMERICA” are nearly touching, known as a “Close AM” design. Normally, for 1992 pennies, these letters should have a noticeable gap. In this error, a die intended for 1993 pennies (where the “Close AM” design was standard) was accidentally used, creating a rare anomaly. 

11. 1969-S Doubled Die Lincoln Penny

Estimated value: $30,000+

The 1969-S Doubled Die Lincoln Penny features a noticeable doubling on the obverse, especially on the date, “LIBERTY,” and “IN GOD WE TRUST.” This dramatic doubling resulted from a misalignment during the die-making process, creating a bold, doubled image that is immediately visible to the naked eye. With only a small number of these pennies ever confirmed, the rarity of this coin makes it one of the most sought-after pieces among Lincoln cents. 

12. 1885/84 Liberty Head Double Eagle

Estimated value: Up to $6,000

The 1885/84 Liberty Head Double Eagle is a fascinating and rare overdate error in U.S. gold coinage. On this $20 gold piece, remnants of the previous year’s date —“84”— are faintly visible beneath the final “85.” This is the result of a die that was first engraved with 1884 before being repurposed and overstamped with 1885. This overdate is subtle but discernible under magnification, making it a prized error for collectors.