The 1866 One Dollar pattern coin is a type of collectible coin that was created as a trial or experimental piece, rather than for general circulation. These patterns often feature unique designs or compositions that differ from standard coins, and they were used to test new ideas for coinage. The 1866 patterns are particularly significant in American numismatic history, as they represent innovative designs during a period of transition in the United States' monetary system. Collectors highly value such patterns for their rarity and historical importance.

Item Denomination Series Year Mint
1866 P$1 Transitional, No Motto J-540 $1 (One Dollar) Patterns 1866 Philadelphia