Estimated County Population Changes, 2000-2009

Last updated: Thursday, March 25, 2010. This page has been updated to present the 2009 population estimates.

Among the many important issues at stake for the 2010 census is representation. The population numbers determine how many congressional seats are allotted to each state through a process known as apportionment. These numbers should become available from the U.S. Census Bureau in December, 2010. In the meantime, the Census Bureau releases yearly population estimates, which make it possible to project how many congressional seats states may gain or lose.

Of further interest is how population growth or declines within states may affect representation for areas within states. The U.S. Supreme Court ruled in a series of cases during the 1960s that legislative districts at all levels of government must be of equal population size. Thus, once population shifts are revealed, district lines must be redrawn through a process known as redistricting. By April, 1 2011, the Census Bureau will report the population data necessary to conduct redistricting. It is impossible to know with certainty how district lines will be laid out, since that is a political decision that will be made by the redistricting authority in each state. However, as with apportionment, it is possible to examine Census Bureau population estimates to project which areas within states are gaining or losing population. Because legislative districts must be of equal size, these areas will thus likely gain or lose representation relative to other areas within the same state.

To see how population shifts may affect representation within states, I plot the estimated population change by county from April 1, 2000 to July 1, 2008. Counties that are losing population are shaded in red and areas that are gaining population are shaded in green. I also list the top ten counties gaining and losing population below the map.

These patterns show two important trends for redistricting:

First, areas that are losing population tend to be old Rust Belt major metropolitan areas, with the addition of the Gulf Coast affected by Katrina and Tampa, and tend to be rural areas through much of the county's heartland and through the Appalachia Mountains. The hard-to-see major cities apparently losing population include Baltimore, Philadelphia, and Newark, but do not include Boston, New York City, or Washington, DC. Demographers in Illinois and Ohio attribute the population losses in Chicago and Cleveland to two factors. Gentrification is displacing larger households for smaller households, and grown children of the formerly larger households have fled the urban areas for the suburbs.

Second, areas that are gaining population tend to be found in Western states, Southern cities, and the suburbs of most major metropolitan areas (Buffalo, Pittsburg, and Youngstown defy this trend).

These population patterns suggest a significant increase in representation for suburbanites at the expense of rural and urban people, particularly in states like Georgia, Illinois, Michigan, Ohio, Pennsylvania, and Virginia where suburbs have experienced explosive growth while rural areas in the same state have actually lost population. This shift in representation may have profound consequences for places like my home state of Virginia, where currently downstate representatives outnumber DC suburban representatives in the state legislature. Perhaps not surprisingly, state taxing and spending policies effectively shift wealth from the DC suburbs to areas downstate.

These population patterns suggest consequences for minority representation, too. Some of this growth in places like Arizona, Colorado, and Texas is from Latino populations. It is difficult to know for sure without the actual population counts and other evidence, but I expect that at least some of the districts in these states will have to be drawn to allow for greater Latino representation, per the Voting Rights Act. Furthermore, as young minorities flee urban areas for the suburbs, they are dispersing themselves into these suburban communities. These communities are not as segregated as the urban places where they used to live, and as a consequence it may be more difficult to draw minority districts - particularly African-American districts - per the Voting Rights Act. Again. Since this is a sensitive issue, I want to stress that we will not know if these hunches are true until the census population data are reported. For this reason, it will be all the more important for these urban areas to encourage a complete count of their communities during the census.