This is a list of notable hamburger restaurants. A hamburger is a sandwich consisting of one or more cooked patties of ground meat (usually beef) usually placed inside a sliced hamburger bun. Hamburgers are often served with lettuce, bacon, tomato, onion, pickles, cheese, and condiments such as mustard, mayonnaise, ketchup, and relish.[1] This list includes restaurants and fast food restaurants that primarily serve hamburgers and related food items.