February 25th people have a bowl & spoon ready to be filled with clam chowder & enjoy National Clam Chowder Day. Clam chowder is a soup or stew with clams or fish & most common clam chowder has milk or cream & potatoes, but Manhattan clam chowder has tomatoes. Clam chowder variants: New England clam chowder; Manhattan clam chowder; Rhode Island clam chowder; Delaware clam chowder; New Jersey clam chowder; Hatteras clam chowder; Minorcan clam chowder; Long Island clam chowder; Puget Sound clam chowder.