This is a list of 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. This list includes restaurants and fast food restaurants that primarily serve hamburgers and related food items.