Fixing prison-based gerrymandering after the 2010 Census: Montana

50 State Guide, March 2010

Impact at the state level
Montana 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:

  • Without using prison populations as padding, 4 Montana House districts drawn after the 2000 Census did not meet constitutional population requirements.
    • For example, each House district in Montana should have had 9,022 residents. District 85, however, has only 7,714 actual residents.
  • Crediting all of Montana’s incarcerated people to a few locations, far from home, enhances the political clout of the people who live near prisons, while diluting voting power of all other Montanans.

Montana law says a prison cell is not a residence:

  • “An individual may not gain or lose a residence while kept involuntarily… as a result of being confined in any prison.” (Montana Annotated Code § 13-1-112(2).)


  • 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 Montana 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:

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