The McDonald's #1 Store Museum is housed in a replica of the former McDonald's restaurant in Des Plaines, Illinois, opened by Ray Kroc in April 1955. The company usually refers to this as The Original McDonald's, although it is not the first McDonald's restaurant but the ninth; the first was opened by Dick and Mac McDonald in San Bernardino, California, in 1940, while the oldest McDonald's still in operation is the fourth one built, in Downey, California, which opened in 1953. However, the Des Plaines restaurant marked the beginning of future CEO Kroc's involvement with the firm. It opened under the aegis of his franchising company McDonald's Systems, Inc., which became McDonald's Corporation after Kroc purchased the McDonald brothers' stake in the firm.

The actual Des Plaines restaurant was demolished in 1984, but McDonald's realized they had a history to preserve, so they built a replica. With golden arches soaring over a glass and metal, red-and-white tiled exterior, the building largely follows the McDonald brothers' original blueprints, which they had introduced when they began franchising in 1953; a Phoenix, Arizona, restaurant was the first built in this manner. Kroc's restaurant was the first McDonald's built in a colder climate, and some adaptations were made to the design, including a basement and a furnace.

The entrance sign is original, with early cartoon mascot "Speedee," representing the innovative Speedee Service System, inspired by assembly-line production, the McDonald brothers had introduced in 1948. It has, however, been moved from its original location at the south end of the property. The sign boasts "We have sold over 1 million." The replica museum offers irregular summer hours and is often closed; tours are by appointment. The ground floor exhibits original fry vats, milkshake Multimixers (which Kroc had sold when he first encountered the San Bernardino McDonald's restaurant), soda barrels, and grills, attended to by a crew of male mannequins in 1950s uniforms. Visitors can walk in through the back or peek through the order windows in front (there was no sit-down restaurant section in 1955). In the basement is a collection of vintage ads, photos, and a video about McDonald's history.

A new, modern McDonald's was built across the street, replacing a Howard Johnson's restaurant (then Ground Round). Over at the new McDonald's there are a half dozen glass-enclosed exhibits arrayed around the tables, including red and white tiles from the original restaurant and string ties worn by employees from the 1950s to the early 1970s.