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

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

In every neighborhood in New York City, from Red Hook in Brooklyn to Riverdale in the Bronx, Vice President Kamala Harris received markedly fewer votes than Joseph R. Biden, Jr. did in 2020, while in most neighborhoods, Mr. Trump notched modest increases compared with 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 that were cast in person, both on Election Day and before, and a majority of absentee ballots, according to Vincent M. Ignizio, the deputy executive director of the city’s election board.

As it stands, the downturn in votes for the Democratic candidate was six times the size of Mr. Trump’s gains when compared with 2020. In some boroughs, the ratio was even larger.

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 started to drop. As of this month, there were about 230,000 fewer active registered Democrats in the city than there were in 2020, and about 12,000 more registered Republicans.

It is not clear how much that contributed to the outcome of the election, but the pattern of Democratic losses and Republican gains was clear across all income levels and ethnic groups in the city. The drop-off was most pronounced among working-class immigrant groups who live outside Manhattan, many of them in the neighborhoods that were hit the hardest by the pandemic and the economic disruption that followed.

The neighborhood where Democratic turnout dropped 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 Mr. Trump increased only slightly, from about 22,200 votes in 2020 to 22,700 in 2024, turnout for the Democratic candidate dropped 46 percent, from about 7,600 votes in 2020 to about 4,100 in 2024.

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

Ms. Harris lost substantial support in precincts with larger populations of Latino and Asian voters. Asian voters have been shifting rightward in recent years because of a mix of concerns about crime, city education policies and the economy.

Mr. Trump made significant gains in precincts where a majority of residents were Latino or Black.