The US Census Bureau recently released its estimates of how the populations of America's counties and cities changed between July 1, 2013 and July 1, 2014.
The Census Bureau includes estimates of the different components of population change. One of those components is net domestic migration: how many people moved into an area from another part of the US minus how many moved out of that area. This tends to be the biggest component of population change in most counties.
It turns out that lots of people moved to Florida, some of the big cities in other parts of the South, and the oil-rich areas of North Dakota and Texas.
This map shows net domestic migration for each county, adjusted by 2013 population:
Here are the fifteen counties with the biggest population adjusted net gains from domestic migration. Five of these counties are in North Dakota:
And here are the fifteen counties with the biggest population-adjusted net losses. Several of these had very small populations to begin with, and so their losses to migration hit hard:
