Mr. Romney won a single Manhattan precinct outright, a stretch of Park Avenue near the Waldorf-Astoria, where six voters showed up and four chose the Republican. But he suffered a resounding defeat in New York, a rare outbreak of consensus in a city famous for fevered disagreement: in 91 of the city’s 5,286 precincts, Mr. Obama received 100 percent of the vote.

Still, even this most Democratic of cities has its outliers and intrigues. A precinct-by-precinct examination of the ways New Yorkers voted this month revealed some anomalous, and often telling, outcroppings, including pockets of red-state America tucked inside fields of blue.

Take a four-square-block slice of Gravesend, Brooklyn, a warren of high-priced residences dotted with Sephardic temples and yeshivas that happens to be the deepest single bloc of Republican support in all five boroughs. On Election Day, 97 percent of the voters there supported Mr. Romney, who beat Mr. Obama 133 votes to 3. Mr. Romney won unanimously in six other precincts, but altogether, 10 people voted in those precincts.