What years does US quarters have Mint marks?

U.S. quarters have included mint marks since 1932, with the exception of certain years during World War II when the production of coins was affected. Mint marks are typically found on the reverse side of the coin, indicating where the quarter was produced: Philadelphia (no mint mark), Denver (D), or San Francisco (S). The use of mint marks has varied over the years, with some specific series or commemorative issues featuring them while others do not.