Fixing prison-based gerrymandering after the 2010 Census: Missouri

50 State Guide, March 2010

Impact at the state level
Missouri law says a prison cell is not a residence
Additional resources

Prison-based gerrymandering violates the constitutional principle of "One Person, One Vote." The Supreme Court requires districts to be based on equal population in order to give each resident the same access to government. But a longstanding flaw in the Census counts incarcerated people as residents of the prison location, even though they can’t vote and aren’t a part of the surrounding community.

When legislators claim people incarcerated in their districts are legitimate constituents, they award people who live close to the prison more of a say in government than everybody else.

Impact at the state level:

  • St. Louis City contains 6% of Missouri’s population, but 15% of the state’s prisoners come from the city. Similarly, Jackson County contains 11% of Missouri’s population, but 13% of the state’s prisoners come from the county. The political effect of this disproportionate incarceration rate is magnified by the fact that very few prisoners are incarcerated in either Jackson County or the city of St. Louis.
  • After the 2000 Census, each House district in Missouri should have had 34,326 residents. District 113, which claimed the populations of 2 large prisons, however, had only 30,014 actual residents. This means that the actual population of the district was 10% smaller than the average district in the state.
  • Crediting all of Missouri’s incarcerated people to a few locations enhances the political clout of the people who live near prisons, while diluting voting power of all other Missourians.

Missouri law says a prison cell is not a residence:

  • “For the purpose of voting, no person shall be deemed to have gained or lost a residence by reason of his presence or absence while… confined in public prison.” (Missouri Constitution, Article VIII, § 6.)


  • Ideally, the U.S. Census Bureau would change where it counts incarcerated people. They should be counted as residents of their home — not prison — addresses. There is no time for that in 2010, but Missouri should ask the Census Bureau for this change for 2020.
  • After the 2010 Census, the state and its local governments should, to the degree possible, count incarcerated people as residents of their home communities for redistricting purposes. Where that is not feasible, incarcerated people should be treated as providing unknown addresses instead of being used to pad the legislative districts that contain prisons.

Additional resources:

  • A list of new large prisons built in Missouri since the 2000 Census. These prisons are likely to create new prison-based gerrymandering problems after their populations are counted in the 2010 census.

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