If you remember the Mazzini Hotel from The Gilded Hour (where the Italian Benevolent Society met), you wouldn’t have any way to know that there really was a hotel by that name on the spot on the south border of Washington Square Park in the early 1880s. That whole neighborhood, south of the park and north of Houston, was home to many immigrants and was ethnically very diverse at that time.
The city’s largest group of French and French Canadians was there, as well as a long established African American community that first began to come together when this was still the outskirts of the city. Italians were also well represented, with fewer Irish and almost no Germans. This larger area is important in the sequel to The Gilded Hour, as is the area around the Jefferson Market (to the east of the park) which you will be familiar with already. This map indicates that the Jefferson Market area and the neighborhood tmoving north along Sixth Avenue was populated primarily by non-immigrants.
Note that the color bars don’t map to particular streets; they are meant only to provide relative densities for the different ethnic populations.
This is a detail from a very large map, one that is quite hard to read. I’ve reconstructed the data to the best of my ability and on the basis of additional research.