How The American Population Changed In One Year

Last week, the U.S. Census released its annual estimates of population change in each of the nation's counties for the year between July 1, 2012 and July 1 2013. The results are fascinating.

This map shows the total net population change, adjusted by 2012 population for each U.S. county:

Population change within counties comes from three sources: natural change - total births minus total deaths, domestic migration - people moving from one county to another, and international migration - people moving to and from other countries.

University of New Hampshire sociologist and demographer Kenneth Johnson wrote in an email to Business Insider that in many counties, natural change is at a historic low:

With fewer births and record deaths, there were not sufficient births to offset deaths in 993 counties (31.6%). Natural decrease (more deaths than births) is more prevalent now because births are diminishing and deaths are on the rise. Nearly 40 percent of the nation's rural counties had more deaths than births last year compared to 18% of the urban counties. This year deaths exceeded births in two entire states. More people died than were born in Maine for the second year in a row and West Virginia again had more deaths than births as it has for a number of years.

Here's a map showing natural population change from births and deaths. A large part of Appalachia saw a natural decline - more deaths than births - while most counties in the West and Alaska saw well more births than deaths.

Professor Johnson also noted that domestic migration is on the rise, and that much of this migration is from urban counties to more far-flung suburbs: "The higher levels of domestic migration are consistent with trends during the 2000s, when suburban areas gained domestic migrants from the older urban cores. They may suggest that the recession's effect on migration is finally beginning to wane."

Here is a map of domestic migration - population change from people moving between counties. It's important to note that this map just shows the total change between July 2012 and July 2013, and doesn't tell us anything about who is moving or which counties are sending people where.

The last component of population change is net international migration - immigrants from other countries moving to a county, minus Americans emigrating to other countries. International migration is most concentrated on the coasts and Florida, and very few counties saw any appreciable net emigration.

We also looked at net international migration in cities here.