History of the hamburger in the United States

A hamburger (or burger) is a sandwich that consists of a cooked ground meat patty, usually beef, placed between halves of a sliced bun or between slices of bread or toast. Hamburgers are often served with various condiments, such as dill relish (condiment), mayonnaise, and other options including lettuce, tomato, onion, pickles, and cheese.
The Texas historian Frank X. Tolbert attributes the invention of the hamburger to Fletcher Davis of Athens, Texas. Davis is believed to have sold hamburgers at his café at 115 Tyler Street in Athens, Texas, in the late 1880s, before bringing them to the 1904 St. Louis World's Fair.
Residents of Hamburg, New York, which was named after Hamburg, Germany, attribute the hamburger to Ohioans Frank Menches and Charles Menches. According to legend, the Menches brothers were vendors at the 1885 Erie County Fair (then called the Buffalo Fair) when they ran out of sausage for sandwiches and used beef instead. They named the resulting sandwich after the location of the fair. However, Frank Menches's obituary in "The New York Times" stated, instead, that these events took place at the 1892 Summit County Fair in Akron, Ohio.
The Seymour Community Historical Society of Seymour, Wisconsin, credits Charlie Nagreen, now known as "Hamburger Charlie", with the invention of the hamburger. Nagreen was 15 when he reportedly made sandwiches out of meatballs that he was selling at the 1885 Seymour Fair (now the Outagamie County Fair) to make it easier for customers to eat while walking. The Historical Society explains that Nagreen named the hamburger after the Hamburg steak, with which local German immigrants were familiar.
There is good evidence that the first hamburger served on a bun was made by Oscar Bilby of Tulsa, Oklahoma, in 1891.
In April 1995, the Dallas Morning News reported on an Oklahoma author who said that Tulsa beat out Texas as the birthplace of the delicacy. Michael Wallis, author of "Route 66, The Mother Road", was quoted by the newspaper as saying that he had discovered Tulsa's place in culinary history, which he made while researching the state’s tastiest hamburgers. He started at the restaurant that has been voted Tulsa's best burger more often than any other restaurant since 1933, Weber’s Root Beer Stand. Wallis’ research revealed that Oscar Weber Bilby was the first person to serve a real hamburger when, on July 4, 1891, ground beef was served on his wife’s homemade buns at a Fourth of July party on his farm, just west of present-day Tulsa. Until then, ground beef had been served in Athens, Texas, on simple slices of bread, known then and presently as a "patty melt". According to the Tulsa-based author, the bun is essential. Therefore, in 1995, Governor Frank Keating cited Athens, Texas' serving of ground beef between two slices of bread as a minor accomplishment. The governor's April 1995 proclamation also cites the first true hamburger on the bun, after meticulous research, was created and consumed in Tulsa in 1891. The Governor's Proclamation cites April 13, 1995, in Tulsa as "The Real Birthplace of the Hamburger." 
The Library of Congress credits Danish immigrant Louis Lassen of Louis' Lunch, a small lunch wagon in New Haven, Connecticut, with selling the first hamburger and steak sandwich in the U.S. in 1895.
Hamburger bun.
The hamburger bun was invented in 1916 by a fry cook named Walter Anderson, who co-founded White Castle in 1921.
U.S. hamburger restaurants.
The following restaurants have either played a part in the creation of the hamburger sandwich, developed a unique cooking method, or were the first to sell them nationwide:
Variations.
In the United States, hamburgers may be classified into one of two primary categories: fast food hamburgers or individually prepared burgers made in homes and restaurants. The latter are traditionally prepared "with everything" (or "all the way", "deluxe", "the works", "dragged through the garden", or, in some regions, "all dressed"), which includes lettuce, tomato, onion, and sliced pickles (or pickle relish). Cheese (usually processed cheese slices, but often Cheddar, Swiss, pepper jack, or blue cheese), either melted on the meat patty or crumbled on top, is a popular option. In the Carolinas a time-honored popular style for hamburgers (and hot dogs) served in diners and homes (but not fast food chains) is "all the way" meaning mustard, slaw, chili and onions.
Condiments may be added to the hamburger or offered separately on the side. The three most common condiments are mustard, mayonnaise, and ketchup. However, salad dressings and barbecue sauce are also popular. McDonald's uses their own "Big Mac sauce" on their signature Big Mac hamburger. Heinz 57 sauce is popular among burger enthusiasts.
Other popular toppings include bacon, avocado or guacamole, sliced sautéed mushrooms, sliced sauce and/or chili (usually without beans). Somewhat less common toppings include fried egg, scrambled egg, feta cheese, salsa, pineapple, Jalapeños and other varieties of chile peppers, anchovies, slices of ham or bologna, pastrami, or teriyaki-seasoned beef, tartar sauce, french fries, onion rings, or potato chips. 
Standard toppings on hamburgers may vary depending upon location, particularly at restaurants that are not national or regional franchises. A "Texas burger" uses mustard as the only sauce, and comes with or without vegetables, jalapeno slices, and cheese. In New Mexico and parts of the Southwest, green chile burgers are very common. In the Upper Midwest, particularly Wisconsin, burgers are often made with a buttered bun, butter as one of the ingredients of the patty, or with a pat of butter on top of the burger patty. This is called a "Butter Burger". In the Carolinas, a Carolina-style hamburger "with everything" may be served with cheese, chili, onions, mustard, and coleslaw. National hamburger chain Wendy's sells a "Carolina Classic" burger with these toppings in these areas. In Hawaii, hamburgers are often topped with teriyaki sauce, derived from the Japanese-American culture, and locally grown pineapple. In areas of the Midwest and East Coast, a hamburger served with lettuce, tomato, and onion is called a "California burger". This usage is sufficiently widespread to appear on the menus of Dairy Queen. In the Western U.S., a "California" burger often denotes a cheeseburger with guacamole and bacon added. Pastrami burgers are particularly popular in Salt Lake City, Utah.
Hamburgers may be described by their combined uncooked weight. A single, uncooked burger weighing a nominal four ounces or 113.5 grams is a "quarter pounder". Instead of a "double hamburger", one might encounter a third- or half-pounder, weighing eight ounces or 227 grams. Burger patties are nearly always specified in fractions of a pound.
In the continental U.S., it is uncommon to hear of a chicken patty or breast on a hamburger bun referred to as a "chicken burger". This is almost always called a "chicken sandwich," except for rare exceptions, such as with the Red Robin chain of restaurants. In Canada, "chicken burgers" generally refer to patties and, when using a chicken breast, to "chicken sandwiches". In Hawaii, small (usually marinated) pieces of chicken piled on a bun are referred to as a teriyaki chicken burger. This is similar to what is found in Japan, but is a local variation.