The oldest still-functioning McDonalds restaurant in America is in Downey, California.It was actually the fourth McDonald's restaurant. The first was in San Bernardino, California in 1940, built by brothers Dick and Mac McDonald. That site is now the location of a combination Route 66/McDonalds museum, but the brothers followed it up with restaurants in Phoenix and North Hollywood before opening their Downey outlet at 10207 Lakewood Boulevard.
The brothers became famous for their "assembly line" approach to cooking hamburgers, and the pioneering restaurant was visited by the later founders of Burger King and Taco Bell. A man named Ray Kroc approached the brothers about creating franchises, and eventually opened his own McDonalds franchise in Illinois in 1955. (Kroc also tried - and failed! - to get a McDonalds restaurant into the Disneyland, based on his wartime friendship with Walt Disney.)
Six years later, Kroc borrowed $2.7 million to buy all the business rights from the McDonald brothers. They were allowed to keep their original restaurant in San Bernardino - but not its name. Their newly-renamed "Big M" restaurant remained open until Ray Kroc opened a competing McDonald's restaurant one block north.
Ironically, their original business agreement would now be worth $100 million a year...
You can catch a glimpse of the arches-in-the-building design in this first McDonalds TV ad from 1962. Ronald is played by a young Willard Scott, who had also played Bozo on a local TV station. Ironically, as the camera pans past the golden arches, you can catch a glimpse of the restaurant's original mascot, "Speedee." (In a white chef hat in the center of the outside arch.)
The first Taco Bell appeared in Downey, California in 1962, followed by restaurants in Paramount and Long Beach. "Seafood & Tacos Raul seems to be the latest incarnation," writes one web page, noting the restaurant's original name was Bell's Drive-In. (The maiden name of the founder's wife!) That site is at 7112 Firestone Boulevard, but the first franchise was in Torrance, California, where Carson intersects Western.