Gold miners in the Colorado Gold Rush needed a place to turn gold dust into money. In 1860, a private firm, Clark, Gruber and Company, opened a mint at 16th and Market Streets that made gold coins.
The US government bought that building in 1863 and used it as an assay office. A new mint was planned in 1896, and construction on Colfax Avenue began in 1897. The first coins were struck on February 1, 1906.
The building is based on the Palazzo Medici-Riccardi in Florence, Italy. Today the Denver Mint is the single largest producer of coins in the world, with a D mint mark on its coins.