Donald J. Trump won 30 percent of the vote in New York City this month. That was a seven-point jump from his 2020 performance, and a higher share of the vote than any Republican nominee has won in the city since George HW Bush in 1988.

But his improved vote share was driven more by the votes Democrats lost than by the votes he gained.

In every borough of New York City, from Red Hook in Brooklyn to Riverdale in the Bronx, Vice President Kamala Harris received significantly fewer votes than Joseph R. Biden, Jr. did in 2020, while Trump saw modest increases in most districts over his last run.

The votes cast in New York City have not yet been certified, but more than 97 percent of them have been counted. That includes all ballots cast in person, both on and before Election Day, and a majority of absentee ballots, according to Vincent M. Ignizio, the deputy executive director of the city’s Board of Elections.

As it stands, the decline in votes for the Democratic candidate was six times as large as Trump’s gains compared to 2020. In some neighborhoods, the ratio was even greater.

Many New Yorkers moved out of the city during the pandemic, and by the 2022 midterms, the total number of registered voters here had already begun to decline. As of this month, there were about 230,000 fewer active registered Democrats in the city than in 2020, and about 12,000 more registered Republicans.

It’s not clear how much that contributed to the election results, but the pattern of Democratic losses and Republican gains was evident across all income levels and ethnic groups in the city. The fallout was most pronounced among working-class immigrant groups living outside Manhattan, many of them in the neighborhoods hardest hit by the pandemic and the economic disruptions that followed.

The neighborhood where Democratic turnout fell the most in terms of percentage change was Borough Park, an Orthodox Jewish enclave in Brooklyn that voted overwhelmingly for Mr. Trump. While support for Trump increased only slightly, from about 22,200 votes in 2020 to 22,700 in 2024, turnout for the Democratic nominee dropped 46 percent, from about 7,600 votes in 2020 to about 4,100 in 2024.

Among income groups in the city, districts with the lowest median incomes saw the biggest drop in support for the Democratic candidate, and the biggest increase in support for Mr. Trump.

Harris lost significant support in areas with larger populations of Latino and Asian voters. Asian voters have been shifts to the right in recent years due to a mix of concerns about crime, the city’s education policies and the economy.

Mr. Trump made significant gains in areas where the majority of residents were Latino or black.