This map is titled "Town of Norwalk, Fairfield Co., Conn.", and comes from an atlas published in 1867 by Frederick W. Beers. I think it's from An Atlas of New York and Vicinity.
The original includes a section that focuses on Winnipauk.
Source: DavidRumsey.com (and on the same site, an 1867 Beers Atlas map focused on South Norwalk)
This map again shows the widow Keeler, now given her proper name Mrs. S. A. Keeler, at the head of Highland, with G. Platt her neighbor to the east in a notably larger house. I'm under the impression these positions are reversed, but it's interesting that the mistake passed from a Richard Clark map to a F. W. Beers map.
At the corner of (what is now) Keeler and Flax Hill you can see Geo Keeler, also known as George Isaac Keeler (1838-1895), the son of Sally Ann Keeler. George was an ice dealer, and his Ice House appears next to (what is now known as) Keeler's Brook. There's a lot more about the Keelers here.
A little further up Keeler is L. Raymond, referring to Lewis Raymond, Jr (1798-1889). He was a stone mason, and on that house there's a plaque with his name on it. Across the street from him is Mrs. P. Hoyt. That's Mary (Polly) Waring Hoyt (1779-1872), Lewis' mother-in-law. Polly's son-in-law Geo. Smith lives next door, and the J. W. Hoyt just up the street is probably her son James Warren Hoyt (1815-1890). Another son, while we're on the subject, was the Geo Hoyt who shows up on Highland.
Sally Ann Keeler's brother Jacob Lockwood had died in 1863, so his property at the corner of Flax Hill and Richards Ave is labelled Est of J. Lockwood.
Across the street from Mrs. Keeler you can see J Tristram. This was Josiah Tristram (1827-1886), a shoemaker born in England. His son William Henry Tristram (1866-1931) would go on to be the postman for the Rowayton area, and lived in this house (now 378 Flax Hill) into the 1920's. Josiah played an innocent role in a train heist in 1866.
M. Scribner is shoemaker Marza Scribner and his family. On earlier maps the Scribners were shown living with Francis Quintard's family, but now the Quintards had moved on.
On this map we now see I. F. Hoyt in the middle of Highland Ave. This is Ira Ford Hoyt (1824-1887), the son of Mrs. H. S. Hoyt up the street. She is Hannah Smith Bouton (1792-1893; Smith was her maiden middle name, not some previous husband), the widow of Aaron Gregory Hoyt (1784-1836). I think her place was 354 Highland. Ira Ford Hoyt was a lumber dealer and contractor who built his home in 1859. His son Dudley was also a contractor, and Dudley's daughter Margaret Rachel Hoyt Smith (1905-2001) was a prominent architect who eventually agreed to sell the property in 1959 to make way for Brien McMahon High School. She ensured that six 100-foot-tall Norway spruce trees planted by her grandfather were retained during the school's construction.
The three households south of I. F. Hoyt on Highland are John Dingee, Dilazon Allen and Major George Hoyt. They'll all go on to play a role in a famous murder on Roton Hill.