Coins are typically marked with a mint mark, which is a tiny letter that identifies where the coin was struck or made. However, not all coins have mint marks. For many years, Philadelphia minted millions of coins without their (P) mint mark simply because they were the only Mint in production, and there was no need to verify the location where the coin was struck. When the Charlotte, Dahlonega, and New Orleans Mint branches opened in 1838, mint marks began to appear on U.S. coins. While coins struck without a mint mark in Philadelphia are not necessarily valuable, there are some instances in which a coin without a mint mark is considered rare and holds value. Here are a few examples of valuable coins with no mint marks:

• The 1922 No-D Lincoln Penny
• The 1968 no-S Roosevelt proof dime (valued between $15,000 and $20,000)
• The 1983 no-S Roosevelt proof dime (valued at around $800)

Its important to note that some coins without mint marks hold value and some do not, so its best to have your coins evaluated by a professional to determine their worth.