
Based on the provided numismatic sources, the 'D' mint mark on a 1921 silver dollar is located on the reverse side of the coin. This side is distinguished by the image of a heraldic eagle with its wings spread, clutching an olive branch and arrows.
Specifically, the mint mark is positioned just below the tail feathers of the eagle and above the letters 'D' and 'O' in the word "DOLLAR," which is inscribed along the bottom rim. The 'D' signifies that the coin was struck at the United States Mint facility in Denver, Colorado. Its placement is central on the lower portion of the coin, situated between the bottom of the wreath and the denomination.


