Redistricting Archive

Collected here are various historical odds and ends relating to the decennial redistricting process.

A note regarding years: A particular vintage of Supervisorial Districts is often identified by just the decade of the decennial Census (e.g. 2000), though in fact it wouldn't have been adopted until the following year (e.g. 2001). You will see both versions of these years represented in these historical documents -- both versions represent the same "vintage".

Redistricting 2020

San Joaquin County encourages public participation in the supervisorial redistricting process!
Please visit for further details and archive materials from the 2020-2021 cycle.

You may use the DistrictR mapping tool to define communities of interest, create redistricting plans, and submit them for consideration by the RAC.

GIS Data: On 8/12/2021, US Census released PL 94-171 Redistricting Data in legacy format. This dataset is very technical nature and quite difficult to use as-is "off-the-shelf". To facilitate public participation in San Joaquin County's 2021 redistricting process we are providing a post-processed version of the PL 94-171 data. The TIGER 2020 vintage geography has been joined to the GEO headers and Segment 1 data file, subsetted for just San Joaquin County, and provided at County, Place, Tract, Block Group and Block levels. Note that even this post-processed version is still quite technical in nature, and requires specialized software to utilize.

Census 2020 PL 94-171 Unadjusted 06077 Redistricting DIY Data Kit (zip)
(Note: This data has not yet been adjusted by CA Statewide Database for incarcerated population reallocations. A separate compilation of adjusted data may be provided here at a later time, following the release of the adjusted data.)

Redistricting 2010


2011-03-09 Initial Fact-Finding

2011-04-04 Population Change 2000-2010 Per District

2011-04-04 Scenario #0 "Existing" (2001 boundaries, 2010 populations)

Initial Scenarios:

2011-04-06 Scenario #1 "Best Match"

2011-04-06 Scenario #2 "Minimize Displacement"

2011-04-06 Scenario #3 "Unify Manteca SD5 (Fails)"

2011-04-06 Scenario #4 "Unify Manteca SD3"

2011-04-06 Scenario #5 "Unify Manteca SD3 Clarify N/S Stockton SD1/2"

2011-04-06 Scenario #6 "Unify Everywhere Simultaneously"

Attempting an actual application of the "Delta in 3 districts" desired criteria:

2011-04-25 Scenario "Delta 3-Way Versus Criteria" 0.975%

Various alternative approaches:

2011-04-28 Scenario "4-28-11 Best Match A 0.107%" 04/28/2011

2011-04-28 Scenario "4-28-11 Best Match B 0.107%" 04/28/2011

2011-04-28 Scenario "4-28-11 Best Match G 0.087%" 04/28/2011

2011-04-28 Scenario "4-28-11 Fix All 6BGs 0.208%" 04/28/2011

2011-04-28 Scenario "4-28-11 JR 1/2 3BGs 2.804%" 04/28/2011

2011-04-28 Scenario "4-28-11 JR 1/2 6BGs 0.278%" 04/28/2011

A strategy was proposed to consider the largest outlier SD5 in isolation first, to better direct the remaining smaller adjustments if a preferred SD5 approach could be selected..

2011-05-04 Scenario "Fix Just SD5 - Existing"

2011-05-04 Scenario "Fix Just SD5 - Along Yosemite"

2011-05-04 Scenario "Fix Just SD5 - Backout Manteca"

2011-05-04 Scenario "Fix Just SD5 - Entire Delta"

2011-05-04 Scenario "Fix Just SD5 - Lathrop Delta"

2011-05-04 Scenario "Fix Just SD5 - Ripon Escalon"

Using the "Along Yosemite" approach for SD5 (see above), a full County-wide scenario:

2011-05-04 Scenario "20110504 0.699%"

More County-wide scenarios based off various SD5 approaches:

2011-05-11 Scenario "20110511A 0.405%"

2011-05-11 Scenario "20110511B 0.977%"

2011-05-11 Scenario "20110511C 0.514%"

Investigative scenarios for various strategy proposals:

2011-05-13 Scenario "Manteca 3-Way" 0.731%

2011-05-13 Scenario "South County 6" 0.240%

2011-05-13 Scenario "South County 7" 0.050%> (best known match to ideal)

2011-05-13 Scenario "Stripes" 0.830%

2011-05-13 Scenario "Unify Neat Lines" 1.447%

Presentation materials:

2011-06-03 Redistricting 2010 Criteria Poster For Public Meetings

Citizen submission:

2011-06-13 Scenario "Keep Cities Whole 7.235%" (Donald W. Parsons)

Alternative version of the 20110504 scenario:

2011-06-20 Scenario "20110504(mod20110620)(step2) 0.173%

The scenario approved by RAC (based off 20110504 work.. based off SD5 "Along Yosemite" work):

2011-07-12 Scenario "20110712(step3)" (As Later Approved) 6.147%

Final Adoption Process:

2011-07-14 Scenario "20110712(step3)" Color

2011-08-01 Scenario "Approved" (aka "Option A")

2011-08-01 Scenario "Manteca" (aka "Option B")

2011-08-01 Supervisorial Districts 2011 (Option A "Approved", sealed, pre-adoption, B&W)

2011-08-01 Supervisorial Districts 2011 (Option B "Manteca", sealed, pre-adoption, B&W)

2011-08-01 Supervisorial Districts 2011 (official, sealed, as adopted, B&W)

2011-08-03 Supervisorial Districts 2011 ("Adopted", Color)

2011-09-13 Supervisorial Districts 2011 ("Adopted" - Retitled, Color)

GIS data:

Supervisorial Districts 2011 (Shapefile)

Redistricting 2000


2001-04-06 Scenario "Existing Conditions" (1991 boundaries, 2000 populations)

Initial Scenarios:

2001-04-25 Scenario #1

2001-04-25 Scenario #2 (as later adopted)

2001-04-25 Scenario #3

2001-04-25 Scenario #4

2001-04-25 Scenario #5

2001-04-26 Scenario #6

Manteca unification strategy considerations:

2001-04-27 Scenario "Manteca in 1"

unification under SD2 was not considered due to contiguity/compactness constraints.

2001-04-27 Scenario "Manteca in 3"

2001-04-27 Scenario "Manteca in 4"

2001-04-27 Scenario "Manteca in 5"

Presentation materials:

2001-05-21 Redistricting 2000 Criteria

Citizen submission:

2001-05-25 Scenario "Bill St Clair"


2003-05-23 Supervisorial Districts 2000 (B&W)

Demographic details:

2002-12-19 Selected Census Values Per Supervisorial District

GIS data:

Supervisorial Districts 2001 (Shapefile)

Redistricting 1990

Supervisorial Districts 1991 Depiction

GIS data:

Supervisorial Districts 1991 (Shapefile)

Redistricting 1980

Supervisorial Districts 1981 Depiction

GIS data:

Supervisorial Districts 1981 (Shapefile)


What Is The "Minimum Majority" Measure?

Supervisorial District Changes 1981 - 2011