What street is the setting of Dr. Seuss's first published book?

The setting of Dr. Seuss’s first published book is Mulberry Street.

“And to Think That I Saw It on Mulberry Street” was first published by Vanguard Press in 1937. Its young protagonist, Marco, walks home after seeing only an ordinary horse and wagon, then imagines an increasingly spectacular parade traveling along Mulberry Street.

The book was the first children’s book written and illustrated by Theodor Seuss Geisel under the name Dr. Seuss. Geisel reportedly developed the story’s rhythmic language while traveling by ship, with the vessel’s engine helping inspire the book’s rolling verse.

Mulberry Street is also the place where Marco’s imagination transforms a simple observation into a zebra, reindeer, elephant, parade and other fantastic sights. Readers sometimes confuse it with a generic fictional street name, but the title’s street is central to the book’s plot and identity. The street was probably inspired in part by a real Mulberry Street in Geisel’s hometown of Springfield, Massachusetts.