1921 Silver Dollar Commemorative Coin Act This bill directs the Department of the Treasury to mint and issue up to 500,000 $1 silver coins in commemoration of the centennial of the re-minting of the Morgan silver dollar that was designed by George T. Morgan and the minting of the Peace silver dollar that commemorated the declaration of peace between the United States and the Imperial German government. Treasury may issue such coins only for a one-year period, beginning on January 1, 2021. All surcharges received from sales of such coins shall be paid as follows: 40% to the American Numismatic Association for numismatic educational activities; 40% to the National World War I Museum and Memorial in Kansas City, Missouri, to educate and commemorate activities related to World War I and its enduring impact; and 20% to the Nevada State Museum in Carson City, Nevada, to support the preservation of the historic features of the museum related to the U.S. mint, the design of interpretive programs that connect visitors to the significance of minting in the United States, the Comstock Lode, and the American West, and to support the activities of the Nevada Division of Museums and History.