COSTA MESA, CA.- The 1804 dollar—long revered as the “King of American Coins”—has captivated collectors and historians for nearly two centuries. Initially struck exclusively for diplomatic distribution, including to the King of Siam (Thailand) and the Sultan of Muscat in modern Oman, collectors clamored for examples of this renowned rarity even before the Civil War. Several books have been published about this coin alone, and the census of the 15 known specimens has been gospel for generations.

Until now. Hidden from view in a mostly forgotten collection since the 1940s, this newly discovered 16th specimen is forecast to bring millions of dollars at auction. It will be displayed for the first time ever by rare coin auction house Stack’s Bowers Galleries at the biggest rare coin gathering in the world, the American Numismatic Association’s World’s Fair of Money™, to be held next week in Oklahoma City. This discovery marks one of the most important “coin” events in modern history.

The 1804 dollar has fascinated American numismatists (coin enthusiasts) since the 1840s, when officials at the United States Mint in Philadelphia first published an image of one. Their story begins not in 1804, but in 1834, when the administration of Andrew Jackson requested sets of coins to distribute to world heads of state. At that time, no silver dollars had been struck since 1804, so the Mint decided to produce brand-new silver dollars displaying that date to be the centerpiece of the diplomatic presentation sets. What Mint officials at that time didn’t know was that none of the dollars struck in 1804 bore the date 1804 (most were likely dated 1803), so the silver dollars made in 1834 that were dated 1804 were the first dollars bearing that date ever made. They became instant rarities. When their production was publicized, collectors clamored to have one — but no crowned head of state was selling.

Employees of the U.S. Mint filled the demand by striking a small number of 1804 dollars off the books for direct sale to collectors. Elaborate false histories of their provenance were concocted. In all, eight examples are thought to have been coined ca. 1834, and seven more were known that showed indications they were made for collectors in the 1860s or 1870s. Researchers have spent over a century piecing together the story of these coins, separating fact from fiction and identifying intentionally false information that became part of the intricate narratives of these pieces.

The attention made the 1804 dollars the most famous coins in the world, which served to also make them the most valuable. At most points in history, since the first auction appearance of an example in 1867, the world record for most valuable coin ever sold at auction has been an 1804 dollar. The last example sold, the famous Sultan of Muscat example, was auctioned by Stack’s Bowers Galleries in August 2021 for $7.68 million. The newly discovered example, thought to have been struck in the years following the Civil War, is forecast to bring $3 to $5 million.

On December 9, 2025, Stack’s Bowers Galleries will auction the newly discovered 16th example of this legendary rare coin, the first new specimen identified since the example presented to the King of Siam was discovered in 1962. This treasured rarity has been held by the heirs of a New York collector named James A. Stack, Sr. (no relation to the founders of the firm) since his death in 1951. While portions of the James A. Stack Collection have been sold over the years, no numismatic expert had any idea of this coin’s existence, upending decades of scholarship and setting the stage for a record-breaking auction.