Collectible coins from the United States, particularly those from the Denver Mint, encompass a variety of types, including commemorative coins, circulating coins, and special edition releases. The 2017 issue may refer to specific series or designs that were minted that year. A "roll" typically contains 25 coins of the same denomination, making it popular among collectors for its convenience and potential for acquiring uncirculated specimens. Collectors often seek coins that have historical significance, rarity, or variation in minting, such as those marked with mint marks indicating their origin.