California Redistricting Patterns by Region

The coming redistricting in California will see two significant forces working to give the new lines.  The first is population, how it has grown and shifted since the last maps were drawn.  The second is the commission process that will follow set rules around keeping cities and counties together, compactness, communities of interest, and drawing lines without considering where candidates live.

To survey the political landscape I put together this chart showing population growth in each congressional district.  While the commission does not need to start from the existing lines, this does show the disparity in population growth among current districts.

Swing State readers should quickly realize that districts with the greatest overages are Republican.  This is seen statewide where Republican congressional seats are on average 42,000 over target population, and Democrat-held seats are 28,000 under.

Tightly packed Democratic seats like those in Los Angeles will have to geographically expand, stealing population from other neighboring Democrats to gain the requisite number of residents.  Conversely, Republican districts will be contracting as they give up voters, and could provide more opportunity to other Republicans.

Current Congressional Districts and Variation from 2010 Projected Targets

Member Residence Variation

1 Mike Thompson D St Helena Under By 19,552

2 Wally Herger R Chico Over By 23,927

3 Dan Lungren R Gold River Over By 52,873

4 Tom McClintock R Elk Grove Over By 78,971

5 Doris Matsui D Sacramento Over By 21,151

6 Lynn Woolsey D Petaluma Under By 82,302

7 George Miller D Martinez Under By 47,071

8 Nancy Pelosi D San Francisco Under By 28,457

9 Barbara Lee D Oakland Under By 47,004

10 John Garamendi D Walnut Grove Under By 4,079

11 Jerry McNerney D Pleasanton Over By 68,602

12 Jackie Speier D Hillsborough Under By 73,416

13 Pete Stark D Fremont Under By 59,603

14 Anna Eshoo D Atherton Under By 47,104

15 Mike Honda D San Jose Under By 17,541

16 Zoe Lofgren D San Jose Under By 7,756

17 Sam Farr D Carmel Under By 63,360

18 Dennis Cardoza D Merced Over By 27,745

19 George Radanovich R Mariposa Over By 49,586

20 Jim Costa D Fresno Over By 18,060

21 Devin Nunes R Tulare Over By 75,114

22 Kevin McCarthy R Bakersfield Over By 71,524

23 Lois Capps D Santa Barbara Under By 54,321

24 Elton Gallegly R Simi Valley Under By 29,472

25 Howard McKeon R Santa Clarita Over By 4,084

26 David Dreier R San Dimas Over By 10,372

27 Brad Sherman D Sherman Oaks Under By 41,458

28 Howard Berman D Los Angeles Under By 37,913

29 Adam Schiff D Burbank Under By 39,041

30 Henry Waxman D Los Angeles Under By 31,871

31 Xavier Becerra D Los Angeles Under By 55,157

32 Judy Chu D Monterey Park Under By 54,149

33 Diane Watson D Los Angeles Under By 36,444

34 Lucille Roybal-Allard D Los Angeles Under By 47,705

35 Maxine Waters D Los Angeles Under By 39,585

36 Jane Harman D Los Angeles Under By 34,005

37 Laura Richardson D Long Beach Under By 36,943

38 Grace Napolitano D Norwalk Under By 51,103

39 Linda Sanchez D Lakewood Under By 44,407

40 Ed Royce R Fullerton Under By 37,637

41 Jerry Lewis R Redlands Over By 100,829

42 Gary Miller R Diamond Bar Under By 10,593

43 Joe Baca D Rialto Over By 57,355

44 Ken Calvert R Corona Over By 191,982

45 Mary Bono Mack R Palm Springs Over By 200,712

46 Dana Rohrabacher R Huntington Beach Under By 40,074

47 Loretta Sanchez D Anaheim Under By 43,323

48 John Campbell R Irvine Over By 437

49 Darrell Issa R Vista Over By 65,129

50 Brian Bilbray R Carlsbad Over By 13,076

51 Bob Filner D San Diego Over By 7,693

52 Duncan Hunter R Lakeside Under By 25,845

53 Susan Davis D San Diego Under By 25,626

The following shows variations for congressional districts by region, however they do not match county growth perfectly as several Congressional districts overlap counties and skew the numbers.

Variation from Ideal 2010 Population, by Congressional Districts in Regions

.: Northern California +4.5% 4 districts over by 175,000, 1 under

.: San Francisco Bay -5.8% 11 districts are under by 415.000

.: Central Valley +6.9% 5 districts over by 240,000

.: Los Angeles -5.5% 13 districts under by 550,000

.: Orange County +1.4% 1 district is over, 4 are under

.: San Diego +1% 2 districts are under, 3 over

.: Inland Empire +11.4% 8 districts are over by 640,000

Regional Differences…

San Francisco Bay Area

Bay Area congressional districts have largely not kept up with statewide growth, putting them under the required population by about 4.5%.  The only exception is the Jerry McNerney district, but the growth in this district is primarily within the San Joaquin portion.  Excluding McNerney, the remaining ten districts need to expand to capture another 415,000 residents.  

Excluding the McNerney district the remaining Bay Area seats have to grow 6% on average.  This does not seem significant when looked at for an individual district where it is like adding the city of Pacifica.  However, as each district takes from the next, the impact is added up.  In the end the last district is going to shift by the equivalent of gaining or losing a city the size of Oakland.

Central Valley and Norcal

Tightly packed urban Democratic seats like those in the Bay Area will have to geographically expand, stealing population from other neighboring Democrats to gain the requisite number of residents.  Conversely, Republican districts like these in the Central Valley and Northern California will be contracting as they give up voters, and could provide more opportunity to other Republicans as these regions add a district.

Aside from population, the requirements for geographic compactness and keeping cities and counties together will wreak havoc on the current districts.

Los Angeles

As can be seen above, the cumulative impact of shrinking population is that LA districts have to go searching for an additional 540,000 residents.   In a redraw that follows the new commission rules this should cause the loss of one congressional seat for the region.

The greatest volatility could come in the San Gabriel Valley where population growth has been slowest. The districts of Grace Napolitano (CD 38), Judy Chu (CD 32) and Xavier Becerra (CD 31) have only had growth of 2-2.5% – putting them under the state average by approximately 8%.  Furthermore, South and West facing beaches limit the ability for districts in the City of LA to move in either of those directions, meaning that expanding districts must shift North and East – likely toward the Inland Empire that has seen the highest growth rate in the state.

The only district in Los Angles with an overage is also the only district held by a Republican.

Orange County

Orange County congressional districts have largely not kept up with statewide growth putting them under the required population by about 5%.  The only exception is the Ken Calvert district, but the growth in this seat is primarily within the Riverside portion of the district.  Excluding Calvert, the remaining five districts need to expand to capture another 130,000 residents.

While Orange County currently has six congressional members, it only has four who live within the county.  The districts held by Miller and Calvert extend from Orange County into Riverside and San Bernardino where those members live.  Given Orange County population estimates, the county should have 4.25 members of congress.  

San Diego

Overall growth in San Diego is just 1% above the state average.  Yet that shifts to about 1% under the state average after accounting for the Issa District that overlaps with Riverside and the Filner district that takes in the Inland Empire.  As can be expected, it is the southern, more densely populated portion of San Diego that has had the least growth.

Inland Empire

Past redistricting efforts have not done a good job of keeping the Inland Empire intact or creating lines that benefit this growing portion of the State.  The area has eight congressional seats with only three districts entirely within its boundaries and five that overlap from Los Angeles, San Diego and Orange Counties.   Half of the Inland Empire’s congressional representatives live outside of the three-county area.

In a redraw that respects city and county lines and pays no regard to where current members live, it can be expected that the three Congressional districts entirely within the Inland Empire would increase to five, and the districts that only dip into the Inland Empire would be stopped at the county lines.  This would be an increase in the region’s true representation, but a decrease in the number of representatives that have any part of the Inland Empire.

19 thoughts on “California Redistricting Patterns by Region”

  1.   Representative Sam Farr is most definitely a Democrat, not a Republican. Nowadays there is no way that a Santa Cruz/Monterey based district would elect a member of the Greedy Old Party to Congress. The last time they had a GOP Rep. was in 1976. That fall the incumbent, Burt Talcott (R-CA), was defeated by Leon Panetta, who served in Congress until joining the Clinton Administration in 1993. He was replaced in a special election by Sam Farr, who is still the Democrat in that seat.

      I remember this well because I was a freshman at UC Santa Cruz and cast my first ever vote for Congress for Panetta in ’76. That fall was the only time in my life that I had a GOP Congresscritter.

  2. There hasn’t been much growth up there, so I imagine CA-13 will get merged with some other district. The Central Valley should gain another seat, centered on Stockton.

  3. raises several questions-oh thanks for posting- and here goes.

    1. What’s the total over/under for each party’s congressman on population change?  Is it like +500K for R congressman?  

    2. Are there numbers out there for Hispanic or AA voters for districts and areas?  I understand that even with the commission that VRA still applies?

    3. I understand that this ballot Prop was designed to stop gerrymanders. Yet the maps of some cities and counties in CA looks a like a bad Gerrymander.  You could actually draw a nice compact district and split certain cities 15 times in three miles.  I wonder how that is going to play out.  I was looking at the map of Santa Fe Springs and Eastern LA county.  Its a jumbled mess.  

  4. Many of the overpopulated R districts went about 50/50 in the 2008 presidential elections. These districts could drop their most liberal precincts into Democratic districts, raising the McCain percentages in a sort of addition-by-subtraction.

    Excellent diary. I never would have guessed that the Inland Empire was growing so fast and that the Bay Area wasn’t growing at all.

  5. I did a preliminary map of disticts, and found that there was a net shift in the Northwest part of LA County between the two areas. Its the off-pink area.  So, to this extent, Northern California gained clout from Southern California.


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