What fictional brownstone address is central to Sesame Street's setting?

The fictional brownstone address central to Sesame Street’s setting is 123 Sesame Street.

The building is the show’s best-known residential location, designed to resemble a New York City brownstone. It is associated with several apartments and has housed characters including Bert, Ernie, and members of the Robinson and Rodriguez families.

The number is sometimes confused with other addresses that appeared in Sesame Street’s broader fictional neighborhood, especially 456 Sesame Street. However, 456 was a separate brownstone used in stories and reference materials; 123 is the signature address tied to the main set and the series’ identity.

The address became so recognizable that “123 Sesame Street” was also used as the title of a Sesame Street syndication package in 1999. In 2019, New York City even designated a real intersection near Sesame Workshop as Sesame Street, though the brownstone itself remains fictional.