What counties are getting Whiter?

[President Punxsutawney Phil]

Fulton County, GA (Atlanta)?

Atlanta is becoming whiter, but the areas to its north are going the opposite direction. So hard to tell I suppose?

[President Punxsutawney Phil]

Are there any populous counties in the U.S. where the percentage of the population that is non-Hispanic Whites is growing?  The browning of America has been a trend for decades, but I was curious to see if any significant areas were actually bucking this trend

My guess would be some super-urban counties in the Acela corridor (i.e., New York, NY; Suffolk, MA; D.C. etc.) may be getting more White, plus maybe somewhere like Wayne, MI or Orleans, LA due to ongoing gentrification? 

Of the states and territories, the only ones which are estimated to have become whiter over the 2010s are DC and South Carolina (an odd juxtaposition indeed).

EDIT: Also, do you insist on non-Hispanic white? Plenty of places have become whiter because more Hispanic (this is true for all five boroughs of New York City, for instance). In some places this has been an extreme change: between the 2010 Census and the 2018 ACS estimate the percentage of Bronx residents who self-identify as white, if you include Hispanic white, went from 28% to 44%. But all five boroughs have become marginally less non-Hispanic white.

EDIT 2: The DC and South Carolina thing is also true only for non-Hispanic whites. At least one fairly prominent state has become whiter because more Hispanic: Florida. I'm sure others have as well but don't really feel like checking manually.

tbf, non-Hispanic White and White are two very different things and it can hurt to be over-exclusive.