“We’re more negative than other researchers who see declines in segregation,” Daniel Lichter, the lead author and a sociologist at Cornell, told me. “I have a hard time putting a positive spin on this research.”

Previous data has suggested that segregation between black and white populations is declining. But much of that research looked at entire metropolitan areas, and found more minorities in suburbs, which led researchers to conclude that the nation was no longer divided into black cities and white suburbs. Lichter and his colleagues looked at at smaller communities, and found that while black residents don’t just live in inner cities anymore, the suburbs they’ve moved to are majority black, while other suburbs are majority white.

“Our substantive point is straightforward,” they write. “Segregation between places (e.g., city-suburb or suburb-suburb) may be increasing, even as overall metro-neighborhood segregation declines.”

In the 1960s, white families moved from cities to suburbs when they saw black neighbors move in next door. Now, they move from suburbs to farther-out fringe areas often not counted in academic studies “hunkering down in all-white neighborhoods, affluent gated communities, or unincorporated housing developments at the exurban fringe,” the researchers write.

And more white Americans, drawn by walkable neighborhoods or transit, are moving back into the inner cities that were once shunned. Young whites and baby boomers, for example, are moving to areas of central cities such as Washington, D.C., which was, for years, a majority-minority city. That, in turn, prices out minority residents.

Segregation isn’t just happening between black and white towns. Hispanic and Asian residents are segregated into their own cities and towns, too. Dover, New Jersey, for instance, a town 30 miles west of New York, was 70 percent Hispanic in the 2010 Census. In 1980, it was only 25 percent Hispanic.

These patterns of segregation are governed by housing practices on individual and municipal levels, like they were 50 years ago. Lenders and real estate agents still steer families to areas with populations of similar races, white families still flee areas with growing minority populations, and family and immigrant networks still attract groups of people similar to themselves.

Over time, communities become known as “black” or “white” or “Asian” or “Latino,” but local policy choices govern some of these categorizations. For example, in Ferguson, Missouri, the percentage of the population that was black increased to 67.4 percent from 25.1 percent between 1990 and 2010. The white population there dropped to 6,206 from 16,454 over the same time period. As whites started to leave, the local government began to allow for the construction of low- and mixed-income housing apartments. Investment firms bought out underwater mortgages and rented the homes to minorities.

“Ferguson became recognized as a ‘black suburb’ that could be distinguished from other nearby suburban communities that made different zoning and administrative decisions,” the authors write.