It’s true, there really once was a 13th Avenue on Manhattan’s West Side—built on landfill in the 1830s starting at about 11th Street and going to 25th Street. Here’s part of it on an 1899 map from the New York Public Library digital collection.
“There are no sidewalks to speak of on Thirteenth-avenue and no surface indications of pavements,” one 1886 article reported. “A foot path winds through it, showing the course pedestrians take to dodge the deeper mud holes in wet weather.”
An 1883 story reported, “[Thirteenth Avenue] begins in a very humble and unpretentious way, but during its brief course of about a dozen blocks it gradually improves in width and general appearance.
“Unfortunately, however, at the very point where it begins to promise great things, and the casual pedestrian feels inclined to fancy it, the avenue ends abruptly in a high board fence, which proves an impassable barrier to all except the most accomplished acrobats.”
The article goes on to describe some of the people who hung around 13th Avenue: Italian immigrant women who pick through trash, night watchmen, and lumbermen.
Exactly when 13th Avenue was de-mapped for good is a mystery.