What is what does it mean when there is no mint mark on a coin?

When a coin lacks a <a href="https://www.wikiwhat.page/kavramlar/mint%20mark">mint mark</a>, it generally signifies that the coin was produced at the main United States Mint facility in Philadelphia. Prior to 1980, the Philadelphia Mint did not include a mint mark on most of its coins, with the exception of the <a href="https://www.wikiwhat.page/kavramlar/wartime%20nickel">wartime nickel</a> (1942-1945), which featured a large "P" to denote its origin. Therefore, if you find a U.S. coin without a mint mark (and it's not a wartime nickel), the default assumption is that it was minted in Philadelphia.

There are a few exceptions or nuances to this rule. For example, some very early coins may have lacked mint marks simply due to the practices of the time. Always research the specific coin series and year to confirm the standard minting practices.