The correlation between a county’s percent Hispanic population and its swing toward Trump was 0.41. Even excluding Miami-Dade County and all of Texas, the correlation is still 0.30. The Bronx, Los Angeles, Osceola County near Orlando, and Hudson and Passaic Counties in Northern New Jersey are all at least 40 percent Hispanic and swung toward Mr. Trump by at least five percentage points.
Urban vs. suburban
Biden’s gains were largest in suburban areas, as was immediately apparent after the election. But because many urban counties have been among the slowest to report their votes, the picture in these counties has become clear only recently.
President Trump did better in 2020 than 2016 not only in Miami-Dade, Los Angeles and the Bronx, but also in Brooklyn, Queens, Manhattan, and the counties encompassing the cities of Chicago, Philadelphia, San Jose and San Francisco.
Though urban counties remain overwhelmingly Democratic, Mr. Trump’s margin improved by 1.1 percentage points in these counties — an even bigger pickup than Trump achieved in non-metropolitan counties, which are largely rural. Thus, the urban-suburban divide narrowed in 2020 — and the urban-rural divide did as well.
Some regional and local patterns offer other possible explanations for 2020 swings.
Home-state loyalties. Arkansas is one of only a half-dozen states that swung toward Mr. Trump. It’s possible that Mrs. Clinton benefited in 2016 from some residual good feeling in the state based on her decade-long term as first lady of Arkansas — something that Mr. Biden couldn’t compensate for. (The Fort Smith, Ark., area was among the top 25 metro areas that swung toward Mr. Trump.)
On the other hand, Mr. Biden appeared to receive a home-state bonus in Delaware, which had the third-biggest swing against Mr. Trump of any state.
New Castle County, with Wilmington as its county seat, moved almost eight points toward Mr. Biden. Why did the Salisbury, Md., metro area have such a big swing against Mr. Trump? One possible reason is that a little more than half of the population of the metro area is across the state border, in Sussex County in Delaware.