Lots for sale on 83rd and 84th Streets at Avenues A and B? That’s not a misprint—York Avenue was Avenue A until the 1920s (and some Avenue A signage still exists, like this school address).
As for Avenue B, based on the faint map on the 1854 ad, it’s the last avenue before the East River.
Manhattan Square? This existed once too at today’s Central Park West in upper 70s and 80s.
In 1852, when this auction was scheduled to be held, it seems to have been part of the sparsely populated village of Harsenville.
What a difference 20 years makes. In the 1870s, it was secured for the site for the American Museum of Natural History, which occupies the four-block square today.
[Vintage ads: Museum of the City of New York Collections Portal]