Clam chowder is any of several chowders containing clams and broth. Along with the clams, potato chunks are common, as are onions and the rendered fat from salt pork. Vegetables are uncommon, but small carrot strips might occasionally be added, primarily for color. A garnish of parsley serves the same purpose.

New England clam chowder typically contains milk or cream as its base. Manhattan clam chowder has tomato in the soup for color and flavor. Clear clam chowders, though less popular than the other two, are still served. Some contend that New England clam chowder has become creamier over the years as a result of tourism in New England, whereas the traditional recipe calls for a soupier chowder. It is claimed that tourists, sometimes squeamish of clams and seafood, prefer the creamier chowder. Throughout the United States, New England-style clam chowder is sometimes served in sourdough bread bowls.