Fixing prison-based gerrymandering after the 2010 Census: Idaho

50 State Guide, March 2010

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:

  • In three legislative districts drawn after the 2000 Census, (District 8 near Clearwater County, District 17 near Ada County, and District 21 near Ada County) at least 2% of each district’s Census population was incarcerated.
  • In District 21, 6.9% of the district’s 2000 Census population was behind bars. Effectively, each group of 93 people in the district were given as much political clout as 100 residents of other districts in Idaho.
  • If uncorrected, the problem of prison-based gerrymandering will be even larger after the 2010 Census. The expansion of old prisons and a large new private prison on South Pleasant Valley Street in Ada County has produced a cluster of almost 4,500 prisoners in what is now district 21. The legislative district that is drawn around these prisons after the 2010 Census could be more than 10% prisoners, giving every group of 9 people near those prisons as much influence as 10 resident in other parts of the state.
  • Crediting all of Idaho’s incarcerated people to a few locations with prisons enhances the political clout of the people who live near prisons, while diluting voting power of all other Idahoans.

Impact at the local level:

  • More research needs to be done, especially in Clearwater County. Unless the prison populations were removed from the redistricting base after the last Census, these communities have one or more districts that are significantly padded with non-resident prison populations. See the Democracy Toolkit for a suggested research methodology. Given the growth of prisons in the county over the last decade, this issue will be even more important after 2010.

Idaho 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… while kept at any state institution at public expense.” (Idaho Annotated Code § 34-405.)


  • 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 Idaho 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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