The Day Mint Marks Returned to American Coins

January 4 • American Coin History Calendar

For three years, one of the most familiar clues on American coins disappeared. There were no D or S mint marks on the nation's 1965, 1966 or 1967 circulating coinage—even though coins were still being produced outside Philadelphia. On January 4, 1968, the U.S. Mint publicly marked their return, ending an unusual experiment born from a national coin shortage.

A Tiny Letter With a Big Job

A mint mark is easy to overlook. On many American coins it is no more than a tiny letter tucked beside a portrait or beneath a design. Yet that letter can tell a collector where a coin was made, help historians reconstruct Mint production, and sometimes mean the difference between an ordinary coin and an important rarity.

By the twentieth century, collectors were accustomed to seeing letters such as D for Denver and S for San Francisco. Philadelphia traditionally used no mint mark on most circulating coins. Then, in the middle of the 1960s, the government deliberately removed mint marks from American coinage.

The reason was not a design experiment. It was part of the federal response to a serious shortage of coins.

During the early 1960s, demand for coins surged. The American economy was growing, vending machines and other coin-operated equipment were becoming increasingly common, and the Mint struggled to supply enough cents, nickels, dimes, quarters and half dollars for commerce.

At the same time, the market price of silver was putting pressure on the traditional precious-metal coinage system. Dimes and quarters still contained 90 percent silver, as did half dollars. Rising silver prices created fears that the metal in the coins could eventually become worth as much as—or more than—their face value.

Government officials also blamed coin collectors and speculators for removing coins from circulation. Whether collectors deserved the amount of blame directed at them has been debated ever since, but Washington's policy response was unmistakable: make collecting newly issued coins by mint less attractive while the Mint concentrated on producing enormous quantities for commerce.

Why Collectors Became Part of the Government's Theory

To understand the mint-mark suspension, it helps to remember how collectors build sets. A person who wanted one example of every date and mint needed to remove a Philadelphia coin, a Denver coin, and a San Francisco coin whenever all three facilities produced a denomination.

During a shortage, officials saw that behavior as potentially counterproductive. A mint mark could turn an otherwise interchangeable piece of money into a distinct collectible. Removing the identifying letters was intended to reduce that incentive.

The policy was extraordinary because mint marks had long served both collectors and the Mint itself. The government was deliberately sacrificing information normally carried on the coin in hopes of keeping more pieces in circulation.

The Coinage Act of 1965 transformed American circulating money. It removed silver from the dime and quarter, replacing those denominations with copper-nickel clad coins. The Kennedy half dollar was reduced from 90 percent silver to a 40-percent-silver composition.

The law also prohibited the use of mint marks for a limited period.

That meant a coin's appearance would no longer reveal whether it had been produced at Philadelphia, Denver or, in certain cases, San Francisco. The policy was intended to discourage collectors from pulling coins out of circulation simply to obtain examples from each mint.

Another extraordinary measure added to the confusion: the Mint continued producing coins dated 1964 well after the calendar had moved beyond 1964, then later produced coins dated 1965 while the actual year was 1966. Dating coins normally seems straightforward, but the shortage temporarily broke the usual relationship between the date on a coin and the year in which it was struck.

The emergency legislation did more than alter metal and suppress mint marks. Congress also restricted changes to coin designs during the shortage period. The objective was stability and production: the Mint was supposed to make enormous quantities of usable coins, not encourage new waves of collecting through design changes.

This helps explain why the mid-1960s feel so unusual in American numismatics. Several practices that collectors normally use to organize coins—date, mint, composition, and collector format—were all disrupted at roughly the same time.

The result was a brief period in which the government's overriding concern was simply restoring an adequate supply of coins to commerce.

1965, 1966 and 1967: The No-Mint-Mark Years

For circulating U.S. coins dated 1965, 1966 and 1967, collectors could no longer use a D or S to identify the producing facility. The absence of a mint mark did not necessarily mean Philadelphia.

That point remains important today. On many earlier and later U.S. coins, no mint mark usually indicates Philadelphia. Applying that rule automatically to the mid-1960s can be misleading because the government intentionally suppressed mint marks during this period.

The experiment also interrupted normal collector products. Traditional Proof Sets were discontinued after 1964 so Mint resources could be concentrated on producing circulating coinage. Instead, the Mint offered Special Mint Sets for the 1965–1967 issues. These were better prepared than ordinary circulation coins but were not traditional proofs.

For collectors, the mid-1960s therefore form a distinctive miniature era: no mint marks, no regular Proof Sets, unusual dating practices and a major transition from silver to clad coinage.

The disappearance of the S mint mark did not mean San Francisco had disappeared from the nation's coin-production system. The facility contributed to the effort to overcome the shortage, but its circulating output could not be identified by an S on the coins themselves during the suppression period.

This is one of the reasons modern collectors have to be careful when interpreting 1965–1967 pieces. The visible coin does not necessarily disclose its manufacturing origin.

When the S returned in 1968, however, San Francisco's role was changing. Its strongest modern association would become proof coinage rather than the huge circulating outputs for which Philadelphia and Denver were known.

Collectors did not receive ordinary annual Proof Sets in 1965, 1966 or 1967. Instead, the Mint sold Special Mint Sets, now commonly abbreviated SMS.

They were a compromise. The coins received more care than ordinary circulation strikes, but the Mint avoided the full traditional proof-making process while production resources remained focused on the shortage.

Today those sets are collectible precisely because they document an abnormal period. Their finish can vary, and especially attractive examples can show strong contrast, but they should not simply be described as normal proofs.

Their three-year existence gives collectors a compact way to study the emergency era from beginning to end.

Congress Allows the Mint Marks to Return

By 1967, the emergency had eased. Congress repealed the prohibition on mint marks, clearing the way for their restoration on coins dated 1968.

The U.S. Mint's own annual report recorded the legal sequence clearly: the Coinage Act of 1965 had eliminated mint marks, and Public Law 90-29, approved June 24, 1967, permitted them again.

The restoration was more than a favor to collectors. The Mint emphasized an operational reason as well. A mint mark identifies the institution that produced a coin, making it useful for production control and accountability. If a problem appeared on coins from one facility, identifying their origin mattered.

On January 4, 1968, Mint Director Eva Adams and Denver Mint Superintendent Marian Rossmiller presided over a ceremony at the Denver Mint showcasing the new 1968 coinage.

The Treasury Department's press release announced that the 1968 coins would carry mint marks for the first time since coins dated 1964.

Denver's circulating coins again displayed the familiar D. Proof coins made at the San Francisco Assay Office displayed an S. Philadelphia continued the longstanding practice of generally issuing its circulating coins without a mint mark.

To collectors who had spent three years looking at anonymous 1965, 1966 and 1967 issues, the return of those letters restored an important piece of each coin's identity.

The 1968 restoration also brought a significant change in placement. Eva Adams directed that mint marks be placed on the obverse—the front—of the coins for greater uniformity.

According to the Mint's January 4 announcement, the cent, nickel, dime and quarter would carry their mint marks to the right of the portrait. On the Kennedy half dollar, the mark would appear below Kennedy's portrait.

This was a departure from older practices in which mint marks frequently appeared on the reverse and in different locations depending on the denomination and design.

Modern collectors take standardized mint-mark locations for granted, but the 1968 change was part of the evolution toward the familiar arrangement seen on later U.S. coinage.

The S Mint Mark Appears on Regular Proof Sets

The January 4 ceremony included another important numismatic first. Officials displayed a specimen 1968 Proof Set bearing the San Francisco S mint mark.

The Mint announced that this was the first time mint marks would appear on its regular proof coinage. Before the 1965 suspension, modern Proof Sets had been produced at Philadelphia and normally carried no mint mark. When traditional proofs returned in 1968, production had shifted to the San Francisco Assay Office.

The five-coin 1968 Proof Set contained specially made examples of the cent, nickel, dime, quarter and half dollar. The Mint initially priced the set at $5, including registered-mail delivery, and limited orders to 20 sets per customer.

The S-marked proof coin soon became a familiar feature of American collecting. San Francisco would become closely associated with modern U.S. proof production.

The return of Proof Sets meant the end of the short-lived Special Mint Set experiment.

Special Mint Sets had filled the collector-product gap during the shortage years. They occupy an unusual place between standard circulation strikes and full proofs and remain a recognizable part of 1960s numismatics.

Once the Mint believed it had enough production capacity to resume traditional collector issues, the SMS program was discontinued. The 1968 Proof Set therefore marked not just a return, but a transition back toward normality after several extraordinary years.

The scale of Mint production helps explain why the emergency measures could finally be relaxed. In the January 1968 announcement, Eva Adams reported that Mint facilities had produced more than seven billion coins during 1967 and more than nine billion during 1966.

That flood of new coinage had largely eliminated the shortage, with the half dollar remaining the major exception. The Mint could once again devote attention to features and programs it had suspended during the crisis.

Mint marks and Proof Sets were among the clearest signs that the emergency period was ending.

Even as the broader shortage eased, the Kennedy half dollar remained difficult to keep in ordinary circulation. Its 40-percent-silver composition still gave the public a reason to save it, and the denomination had additional emotional appeal because it honored the assassinated president.

This helps explain why the January 1968 restoration should not be read as a magical moment when every monetary problem vanished. It marked normalization, but some consequences of the silver transition continued.

The half dollar itself would lose its remaining silver from regular circulation issues beginning in 1971.

1968-D: Common Coins With an Uncommon Historical Meaning

Denver struck enormous quantities of 1968-dated circulating coins. Most are common today, and that can obscure their historical importance.

The D was not merely another mint mark in a long sequence. It was the visible return of a system that the government had intentionally suspended. A 1968-D coin is therefore evidence that the emergency anti-collecting policy was ending.

For a date-and-mint collector, the contrast is immediate: a 1964-D can carry the mark, 1965–1967 cannot, and 1968-D displays it again.

The 1968-S proofs also point forward rather than backward. San Francisco became the facility most closely identified with modern proof coinage, and the S mint mark became a familiar sight in annual collector sets.

That association is so strong today that it is easy to forget how notable it was in 1968. The proof program had been absent for three years, and the returning sets were now coming from a different facility with visible mint identification.

The restoration therefore created a new collecting pattern at the same time it revived an old feature.

Although 1968 moved mint marks to more standardized obverse locations, the method of placing them on working dies was still very different from modern practice.

For decades, Mint employees punched mint marks individually into working dies. Small differences in position, depth, angle, or repeated punching could create varieties that later became objects of specialist study.

Only much later did mint marks become incorporated into master tooling and the hubbing process rather than being individually punched into each working die. The 1968 restoration therefore belongs to an older technical era even though its obverse placement looks familiar to modern collectors.

Collectors often think of mint marks primarily as a way to identify scarce issues. But the letters also preserve manufacturing history.

A D can connect a coin to Denver's production records. An S can identify San Francisco's role. When quality-control questions or unusual varieties appear, knowing the facility can help researchers reconstruct how and where the coin was made.

The no-mint-mark experiment removed that visible trail from 1965–1967. Restoring it gave each facility its identity back on the coins themselves.

The 1964–1968 Run Tells the Whole Story

Few five-year stretches of ordinary U.S. coinage contain as much monetary change as 1964 through 1968.

In 1964, dimes, quarters and half dollars still belonged to the traditional 90-percent-silver system. Then came delayed dates, the disappearance of mint marks, clad dimes and quarters, 40-percent-silver halves, Special Mint Sets, and finally the 1968 restoration of mint marks and proofs.

A collector can place coins and sets from those years side by side and see federal monetary policy unfold physically. The history is not hidden in legislation alone; it is stamped into the metal.

A 1968-D cent or quarter may look ordinary today, but its D represents the return of information that had intentionally been removed from American coins. Likewise, a 1968-S proof represents the beginning of a new relationship between San Francisco and modern proof coinage.

The change also makes the surrounding years easy to recognize as a historical group. A collector looking at 1964 through 1968 can see the upheaval of the decade directly in the coins: traditional silver, missing mint marks, Special Mint Sets, new clad compositions, reduced-silver half dollars, and finally the return of D and S.

Those details turn common coins into historical documents.

Mint marks have existed on American coins since the nineteenth century because a nation with multiple coinage facilities needed a way to identify where its money was made. Removing them in the 1960s was an extraordinary response to extraordinary circumstances.

The policy lasted only a few years.

On January 4, 1968, the Mint publicly celebrated their restoration at Denver. The D returned to circulating coins. The S appeared on San Francisco proofs. Proof Sets returned after a three-year absence. And the strange no-mint-mark chapter of 1965–1967 began to look like what it ultimately became: a short but fascinating episode in American monetary history.

Sometimes the smallest feature on a coin tells one of its biggest stories.

• San Francisco Strikes Coins Again After a Ten-Year Pause
• The First 1965-Dated Cents and Nickels Are Struck
• The Denver Mint Strikes the First 40% Silver Kennedy Half Dollars
• Lyndon Johnson Reappoints Eva Adams as Director of the U.S. Mint