Shifting Seats
How population shifts since 1960 impacted Congressional Apportionment
Congressional representation is reapportioned every ten years following the decennial Census. Reapportionment is the distribution of seats in Congress to the states based on each state's population. States experiencing significant growth increased representation while states with minimal growth or declining population will lose seats. The graphic below shows the change in apportionments of the largest states since the first Apportionment in 1789.
Since 1960, with the admission of Alaska and Hawai'i to the United States, apportionment has distributed 435 seats across 50 states into single-member districts. Below you can see the country broken up into regions and how apportionment has affected each region between 1960 and today.
Within these regions there are slight variations but generally, the United States population has shifted from the Northeast & Great Lakes to the South & West.
The South, Mountain West, and Pacific are all growing rapidly with the Mid-West and Mid-Atlantic regions drastically falling. New England has also lost a handful of seats. The charts below represent the share of the population of each region and how it has changed from 1960-2020.
The Mid-Atlantic is dragged down by the sharp decline in New York (-15) and Pennsylvania (-10). Many of these residents are moving to states across the Sun Belt. West Virginia has seen a 60% drop in representation (from 5 to 2 seats) and New Jersey’s delegation has shrunk by 20% (from 15 seats to 12). New York and Pennsylvania have both seen about a 37% drop in congressional seats. The only state in the region to see any growth is Virginia (from 10 seats to 11).
The midwestern states have seen steady apportionment losses since the Great Depression. The region’s precipitous drop slowed slightly when Michigan and Ohio both gained one seat in 1960, but since 1960 the region has lost 34 seats in Congress. Those losses are led by Ohio (-9), Illinois (-7), and Michigan (-6). Only two states, Nebraska and Minnesota, have the same number of seats after 2020 that they had after the 1960 Census. The Mid-Western states are expected to continue hemorrhaging representation after the 2030 Census
The South has seen explosive growth since 1960. Led by Florida (+16) and Texas (+15) the region’s congressional representation has expanded by 33 seats. Georgia (+4), North Carolina (+3), and South Carolina (+1) have also gained seats. Unlike the Mid-West and Mid-Atlantic, population trends in the South have been less uniform. Kentucky, Oklahoma, Mississippi, and Alabama have all lost a seat. Louisiana has lost two. Tennessee and Arkansas have not changed.
The Mountain West region hasn't seen a single state lose a seat in the last 3 decades with Arizona (+6), Nevada (+3), and Colorado (+4) leading the way. Population growth has been mainly focused in the Phoenix, Las Vegas, and Denver Metropolitan areas. Utah and Idaho had the fastest growth rate in 2020.
The Pacific Coast's growth mostly comes from California (+14) while Oregon (+2) and Washington (+3) have also grown. Hawai'i and Alaska have the same number of seats they had when they joined the Union.
An examination of individual states’ growth or loss reveals more pronounced trends. You can click on each state to see its Census Population Change, Percent growth or loss, and change in number of congressional seats.
The last 60 years' population shifts have also shifted power from some states to others.
The purple states have lost seats since 1960 and the green states have gained seats.
States concentrated in the Northeast have consistently lost seats.
New York, Pennsylvania, and Ohio have lost seats following each apportionment since 1960. New York's 15 seat loss is the most of any state.
Population Forecast* of New York 1910-2100
Population Forecast* of Pennsylvania 1910-2100
Population Forecast* of Ohio 1910-2100
*These forecasts are calculated using population trends and are not official census projections.
The growth rates in these three states continue to level off. If unchanged, the stagnant population trends will lead to the loss of more seats in 2030.
Meanwhile the Southeast has been growing and subsequents apportionments have led to more representation. Florida 16 seat gain is the most of all the states in the Modern Era.
Population Projection of Florida 1910-2100
If Florida continues to rapidly grow it could be double its current size by the end of the Century.
Texas, Arizona, and other Southwestern States have been rapidly gaining seats.
The growth in Texas, Arizona, and Colorado does not seem to be slowing any time soon but trends in California are reversing.
Population Forecast of Texas 1910-2100
Population Forecast of Colorado 1910-2100
Population Forecast of Arizona 1910-2100
Most of these trends are unidirectional with states trending the same way over the last six decades.
California is the lone exception. It failed to gain a seat for the first time in 2010 and lost a seat for the first time in 2020 These were the first times either even had happened since the Golden State joined the Union in 1850.
Population Forecast of California 1910-2100
2022 Population Estimates
In addition to the Decennial Census, the Census Bureau releases different products to provide insights into the American population, economy, & demographics. One of the annual products that helps explain how the population of states and counties have changed is its Population Estimates & Projections.
The Population Estimates & Projections or PEP Survey is produced at the end of each year between Censuses. These estimates are not full counts. The Census Bureau uses the most recent census and different governmental records such as births, deaths, housing units, and migrations to produce an annual look at the population of different geographies. The most recent PEP was released in December 2022 for the July 2022 estimate. This 2022 PEP Survey can provide insights into the potential impacts the yearly population change might have on the next apportionment following the 2030 Census.
The map below includes the results of the 2022 Population Estimates.
State_Populations of the ACS & PEP
While not perfect, these state population numbers can provide some insight into the potential outcome of the 2030 apportionment by forecasting recent growth rates forward to April 1, 2030 (Census Day for the 2030 Census). It is important to note that these forecasts are using the 2020 Census as the baseline. This most recent Decennial Census was plagued with errors including some of the largest miscounts in decades, a problematic privacy algorithm known as "Differential Privacy", and delays in counts and reporting.
If seats were apportioned today using the most recent population numbers from the PEP, four states would gain a seat and four states would lose a seat. The map & chart illustrates those apportionment shifts.
2022 Apportionment Map showing CA, IL, MN, & NY losing a seat while AZ, FL, ID, & TX gaining a seat.
2022 PEP Hypothetical Apportionments
If the 2022 population estimates, and underlying growth rates, are forecast to the next scheduled apportionment in 2030 the results would match the map below.
It is highly unlikely that these projections come true in 2030. Part of these "growth rates" are simple corrections from the errors in the 2020 Decennial census. The massive over & undercounts were remedied in these estimates which creates artificially high population differences between today's estimate and the 2020 baseline. While the exact seats that change are unknown, it is fair to assume the regional patterns will most likely continue to hold. The South and Mountain West are still expected to continue to grow while the Mid-Atlantic & Mid-West will shrink. There is also a strong potential for the Pacific West to shrink.
Read more about apportionment, the Census, and other redistricting related resources with the American Redistricting Project links below. Be sure to check back for more updates on changing populations and redistricting litigation.