To offset gains that Donald J. Trump made in rural and suburban America in 2024, Kamala Harris needed to do better than Joseph R. Biden Jr.’s strong 2020 electoral performance in cities. But she ended up doing worse in urban America — getting 15 percent fewer votes than Mr. Biden in some cities. A New York Times analysis of precinct-level election results — the most detailed available publicly — across 11 cities shows how it happened.

In Atlanta and its suburbs, both candidates found new voters, but Ms. Harris’s gains in precincts where white voters were the largest racial or ethnic group were canceled out by losses elsewhere. Mr. Trump’s uptick in support from voters of color across Atlanta, along with improved performance in the state’s rural areas, was enough for him to win Georgia — a swing state he narrowly lost to Mr. Biden in 2020.

Chicago is emblematic of the chief problem the Harris campaign faced in urban areas — a big decline in votes in Democratic strongholds. Even though Ms. Harris won the city by a 58-point margin, she lost ground in nearly every precinct. She picked up just 127,000 votes in Mexican and Puerto Rican neighborhoods, 47,000 fewer than Mr. Biden earned in 2020. Mr. Trump made small gains across the board, but Ms. Harris’s losses were much steeper.

In Wayne County, which includes Detroit, Ms. Harris struggled to capture the support of Arab-American voters, many of whom had been turned off by the Biden administration’s Middle East policies. In a swath of voting precincts spanning Dearborn and Hamtramck, which have the nation’s highest concentration of people of Arab ancestry, Mr. Trump picked up thousands of votes compared with 2020, while the Democratic Party lost an even bigger number. Countywide, precincts with high shares of Arab residents made up just 6 percent of the electorate but accounted for more than 40 percent of the decline in Democratic votes.

The story in Houston was more about Ms. Harris underperforming Mr. Biden’s 2020 vote totals than about Mr. Trump achieving sharp gains, especially in Latino neighborhoods and lower-income areas. Ms. Harris’s vote total was down 12 percent overall from Mr. Biden’s in 2020, and 28 percent in low-income neighborhoods where Latino voters are the largest group.

In this rapidly growing area, red shifts were most evident in Latino neighborhoods. While Ms. Harris matched Mr. Biden’s vote total overall, Mr. Trump made significant gains throughout the area.

Mr. Trump was already popular with the county’s large Cuban American population, but in this election, his support surged with Latino voters from other groups as well. He received 20 percent more total votes in Latino neighborhoods where Cubans are not the predominant Latino group, like those with large populations of Nicaraguans or Colombians. This helped him flip Miami-Dade County for the first time since 1988, further cementing Florida as a decisively red state.

Mr. Trump saw gains on the city’s South Side, where there are Latino precincts with large Mexican populations, and his increased support coincided with Ms. Harris’s losses there. Ms. Harris picked up votes in some white neighborhoods, but those gains were erased by the losses elsewhere, allowing Mr. Trump to cut into the Democratic margin and flip the state back to the Republican column.

Latino neighborhoods accounted for nearly half of Mr. Trump’s total gains in his home city compared with 2020. While Ms. Harris won these precincts by a 40-point margin, that fell short of Mr. Biden’s 66-point margin in 2020. In a city with a diverse population of Latinos, Mr. Trump’s vote share grew among all of them — Puerto Rican neighborhoods, Dominican neighborhoods and Mexican neighborhoods alike.

Ms. Harris outperformed Mr. Biden in some parts of the city — especially in white precincts near the downtown area. White voters were the largest racial or ethnic group in 24 of the 25 precincts where she gained the most votes. But Ms. Harris lost some support in Latino and Black neighborhoods elsewhere in the city, and the Democratic margin fell to 59 points, from 64 points in 2020.

More than half of the Democratic vote decline occurred in Latino neighborhoods, even though these precincts accounted for just 16 percent of the overall vote total. Ms. Harris still won Latino neighborhoods by 23 points, but it was a 12-point drop from the 2020 margin of Mr. Biden, who narrowly won Arizona, a Republican stronghold won only twice by Democrats since 1952.

Even this city — known for its liberalism and its importance to Ms. Harris’s career — swung toward Mr. Trump. Ms. Harris’s losses were especially noticeable in the city’s Asian neighborhoods, which are predominantly Chinese but include thousands of voters from other groups. Though Ms. Harris still won the city by a 68-point margin, Mr. Trump gained more than 6,000 votes on top of her vote losses.