In 2000, the Library of Congress recognized Louis’ Lunch as the restaurant associated with creating the hamburger.
Louis’ Lunch is a New Haven, Connecticut, restaurant founded by Louis Lassen. Its account says that in 1900 Lassen used ground beef trimmings to make a quick sandwich for a customer in a hurry, serving the patty between slices of toasted bread. The restaurant still presents its burgers in that distinctive style rather than on a conventional round bun.
The recognition did not settle the hamburger’s entire history. Charlie Nagreen, the Menches brothers, Fletcher Davis, and others have competing claims, and historians debate what should count as the first hamburger. Some critics also argue that Lassen’s toasted-bread sandwich differs from the modern bun-based burger.
Louis’ Lunch remains the canonical answer to this specific Library of Congress question. Its old vertical broilers, dating to 1898, are another part of the restaurant’s identity, and traditional toppings include cheese, tomato, and onion.