According to its cartouche, this is:
Clark's Map of Fairfield County, Connecticut
from actual survey by & under the direction of
J. Chace Jr. civ. eng. Troy, N.Y. & W. J. Barker N. Hector New York.
Published by
Richard Clark
307 Wharton St. Philadelphia
1858
The original is a huge map with 6 pages; only the 5th page, the one that includes Norwalk, is shown below.
As in the 1851 map, we again see Widow Keeler at the intersection of (what is now) Highland and Flax Hill Road. Next door is J. Platt, which must indicate George Platt (1812-1873), an English architect and interior designer who had recently moved to Norwalk from New York City. If you walk by these houses today, you'll see that this doesn't really make sense -- the house at the top of Highland has a plaque on it noting that George & Mary Platt lived there. For this and several other reasons, I think these maps have a persistent error, swapping the two houses.
If you look down Highland Ave toward the train tracks, you'll see G. Hoyt and D. Allen. These are Major George Hoyt (1805-1884) and Dilazon Allen (1804-1880), who will play incidental roles in the story of the murder of Johan Heinrich Schulte, which took place 20 years after this map was drawn.