Dave's Redistricting

Do Your Own Redistricting

This is the page for DRA 2.2 and 2.5 (Old DRA). Find DRA 2020 here.

The application runs on Windows and Mac and requires Silverlight 4.0 or later (will ask download if not already there).

Current Version: 2.2.26

Browsers: DRA is built on Silverlight which uses the old plugin API (NPAPI), which many browsers have stopped supporting.

  • IE: Works.

  • Safari: It did work on Yosemite (MacOS 10.8), but on Sierra (10.12) it does not function correctly. I don't know about other versions.(Safari/Preferences/Security/Plugin Settings).

  •  Firefox ESR: 52.9 works. Later versions don't Tools/Addons will take you to the page to manage Addons, including plugins. There you can allow or disallow each plugin (or set it to ask each time). Note: On Mac Sierra, Silverlight runs much slower than before.

  • Chrome: Does not work.

  • Standard Firefox version 52 and above: Does not work.

  • Edge: Does not work.

DRA 2.2 depends on a Bing Maps control that is no longer officially supported. But it still works and I recommend continuing to use it. From what I can glean, it could continue to work for a while, but there's no guarantee now that the control is unsupported. Maps saved in 2.2 can be loaded in 2.5.

The new version, DRA 2.5 does not depend on the Bing Maps control, so should continue to work for the foreseeable future. The main features and data remain, although Alaska does not work correctly. A link and details on what features are still supported are below.

2010 voting districts/block groups available for all states, DC and PR.

Election data for 2010 voting districts (or block groups) available for IN, NC, NM, TX* and AK, AL, AR, AZ, CA, CT, DC, DE, FL, GA, HI, IA, ID, IL, KS, KY, LA, MA, MD, ME, MI, MN, MO, MS, MT, ND, NE, NH, NJ, NV, NY, OH, OK, OR, PA, RI, SC, SD, TN, UT, VA, VT, WA, WI, WV, WY+, and CO++, and PR^

Launch Dave's Redistricting 2.2

Launch Dave's Redistricting 2.5

Browse Maps of various state plans.

(Launch Original Dave's Redistricting App (1.0))

DRA 2.2/2.5 News

Feature Differences of the new DRA 2.5

  • The big difference is you will see no background map. I may be able to put a static map in the background, but that does not work yet.
  • Coloring the map is the same, except double-click to change to/from Color mode does not work.
  • Zoom using the slider on the upper left or using the mouse wheel.
  • Area Maps are no longer supported.
  • Resizing the overall browser window may make pan and zoom function incorrectly.
  • Checking a CD for contiguity is no longer supported.
  • Find unassigned districts doesn't zoom.
  • Loading a DRF ignores the position of moved labels, but size changes are honored.
  • Fixes an issue: a DRF for a map that allows districts with different target populations did not honor the differences. That is fixed in newly saved DRFs.

Known Issues with DRA 2.5:

  • Resizing the browser window can mess up zooming.
  • OldCD labels don't work.
  • Loading a large state may position it somewhat off screen.
  • Close and then Open a DRF does not reset the displayed zoom level.

Main Features of DRA 2.2 and 2.5

The application has a lot of features. You can

  • Select a state and a number of congressional districts (CDs), legislative districts or county council districts.
  • Use the mouse to sweep across map assigning voting districts to CDs
  • Create CDs automatically to match the current CDs
  • Pan/Zoom
  • Save/Open your work in XML
  • Show and Unshow city names, counties, old CDs and more
  • Show the state colored by demographics or election data (if available)
  • Create views of zoomed in areas and save views as JPEGs
  • Change colors and color opaqueness

Version 2.2/2.5 Features

Legislative and County Redistricting

  • You can make a map for LDs (legislative lower house), SDs (legislative upper house) and CCDs (county council).
  • You can see old LDs and SDs.
  • You can switch between CD, LD, SD and CCD scenarios with the Change Scenario button.
  • You can save them all in 1 DRF.
  • You can convert on load a CD map you built (that was really an LD or SD map) into an LD or SD map.
  • You can create CDs or LDs with unequal population (for multi-member districts) by telling the app how many representatives/legislators represent each CD/LD (where each may be different) and the app will set population targets accordingly. Or you can set the population targets for each CD/LD directly.
  • You can create districts for multiple counties in a state. For each county scenario, only the voting districts in that county are shown and colorable, and the population targets are set using the county's population.
  • You can Color Automatically by loading a block, block group or vote district CSV file (block equivalency file).

Other New Features

  • You can do Color By Population and Color By Election for only unassigned voting districts (so you can see the partial CDs/LDs you've made at the same time). The check box for this is on the Tools panel.
  • You can turn off labels on old CDs/LDs. The check box for this is on the Tools panel.
  • If you've made changes to your maps that you have not saved, doing Open, Close, select state or change #CDs/LDs will ask you to confirm to ensure you don't accidently lose your work. (Closing the browser will still not warn you.)


  • Please report bugs, make comments and requests to redistricting@gardow.com
  • The Silverlight 5 runtime seems to use more memory and causes some large states (e.g. California and Texas) to sometimes fail to load. Here's where to find Silverlight 4.0.60831.

Election Data Notes

The Avg shown for each voting district represents the normal 2-party vote split over a set of statewide elections. Which elections varies by state as shown below:

  • AK - 2008 Senate
  • AR - 2010 statewide races for Lt. Gov., SoS, Comm. of Public Lands
  • AZ - All 2010 statewide races plus 2008 Pres
  • CA - 2010 Governor
  • CO - All 2010 statewide races
  • GA - All 2006-2008 statewide races
  • LA - 2008 Pres, Senate, House races
  • MA - 2010 Senate and Governor's races
  • MD - All 2006-2008 statewide races
  • MI - Gov., AG, SoS 2006
  • MN - All 2004-2008 statewide races
  • MO - All 2008 statewide races and House races
  • NC - All 2004-2010 statewide races
  • NE - All 2006 statewide races and House races, and 2008 Pres, Senate and House races
  • NJ - Pres, Gov, Senate 2002-2009
  • NM - All 2010 statewide races
         - Updated voting districts: All 2004-2010 statewide races except 2006 Gov., Sen. and Treas. and 2008 Sen.
  • NV - All 2008-2010 statewide races plus US House races
  • NY - All 2010 statewide races
  • OH - All 2008 statewide races
  • OK - Presidential and Senate 2004-2008, Gov., Lt. Gov., AG 2006
  • PA - All 2004-2008 statewide races
  • PR - 2012 Gov (Dem = PPD, Rep = PNP)
  • SC - All 2008-2010 statewide races
  • TN - Pres, Gov, Senate and House 2004-2008
  • TX - Governor and Presidential races 2002-2010
  • VA - All 2000-2009 statewide races
  • WA - 2010 Senate
  • WI - Senate and Governor races 2010

Sometimes the presidential election vote totals shown in the app are lower than actual vote totals. Usually this is because absentee and sometimes early votes are not reported by voting districts. For GA, SC and TN, this is particularly evident.

California Caveats: presidential data has significant missing votes, especially in LA ad San Mateo Counties. Some votes may be misallocated, too. (Look for DailyKos.com diary by roguemapper for more info.)

Supported States

  • All states supported with Census 2010 data.
  • WA election data is from the 2010 US Senate race only. AK election data is from the 2008 Senate race only.
  • Note: California 2010 data has some voting districts with very large population (60-80 thousand). It's what is in the data. For example, the entire city of Fremont (pop. 84347) is one voting district. Block groups break down the population much better.
  • All states except Alaska are supported with Census 2000 data.
  • States using Census 2000 Voting Districts have only county level new population estimates (from 2008). Most states using block groups have block group level estimates from the 5-year (2005-2009) American Community Survey, which are more accurate. However, no partisan data is available for block groups.
  • States with partisan data using "Special Custom Data" (Census 2000 + population estimates), courtesy of "jeffmd."
    • California
    • New York
    • Texas
  • States with election data with Census 2000 data using regular voting districts
    • Maryland
    • New Mexico
    • North Carolina
    • Pennsylvania

Dave's Redistricting 2.1 Help

Temporary links to 2.0

*IN, NC, NM, TX presidential election data: Stephen Ansolabehere, Jonathan Rodden. <State> 2010 Census Shapefile and Precinct-Level Election Data. Release 2011. Wisconsin 2010 (Avg) data from Wisconsin Democracy Campaign. All other Avg data from Stephen Ansolabehere and Jonathan Rodden.

+AK, AL, AR, AZ, CA, CT, DC, DE, FL, GA, HI, IA, ID, IL, KS, KY, LA, MA, MD, ME, MI, MN, MS, MO, MT, ND, NE, NH, NJ, NV, NY, OH, OK, OR, PA, RI, SC, SD, TN, UT, VA, VT, WA, WI, WV, WY presidential election data by Steve Gerontakis ("roguemapper") with assistance by John Mifflin. WA Senate data from Dave Bradlee. AK Avg (Senate) data from Steve Gerontakis. Any other Avg data from Stephen Ansolabehere and Jonathan Rodden.

++CO presidential data from Tyler Chafee. Avg data from Stephen Ansolabehere and Jonathan Rodden. MA Avg data from Steve Gerontakis.

^PR Avg (2012 Governor) data from Steve Gerontakis, with PPD in blue (Dem) and PNP in red (Rep).

**For updated voting districts: NM election data from NM Legislative Council Service. PA presidential election data from Steve Gerontakis.

Cook PVI data from Decision Desk HQ. Note: For PA, the PVI data goes with original, not updated, voting districts.