25 districts for each census

[kcguy]

1900 Census
PRESIDENT:  William McKinley

Of the existing regions, the 5 largest are (1) TX/LA – 1.46; (2) CA/NV/AZ/UT/OR/WA/ID/MT/WY/ ND/SD – 1.34; (3) WI/MN – 1.26; (4) NYC/Long Island – 1.24; and (5) AL/MS – 1.11.

The 5 smallest are (1) OH East – 0.67; (2) OH West – 0.69; (3) IL South – 0.70; (4) MA North East/ ME/NH/VT – 0.78; and (5) MI – 0.80.



SEAT CHANGES:
SHIFT:  The MA North East/ME/NH/VT region is undersized, so it gains territory from the MA South & West/CT/RI region.
SHIFT:  The NYC/Long Island region is oversized, so it gives territory to NY Southeast/NJ/DE, which gives territory to the NY North & West region.   [NOTE:  In case it’s not visible, the NYC/Long Island region is reduced to Kings and New York Counties.  Unfortunately, I didn’t realize until afterwards that I made Long Island non-contiguous with the rest of its new region.]
LOSS:  The OH East region is disbanded and added to OH West.
SHIFT:  IL South is undersized, so it gains territory from IL North.
GAIN:  The TX/LA region is split in two.  The LA portion gains the MS portion of the AL/MS region.  The AL portion of the AL/MS region gains the FL portion of the GA/FL region.  GA maintains its own region.  The TX portion of the TX/LA region gains NM from the KS/CO/NM/OK/Ind Terr region and gains AZ from the CA/NV/AZ/UT/OR/WA/ID/MT/WY/ND/SD region.  The KS/CO/OK/Ind Terr portion of its region gains UT from the CA/etc region.

[kcguy]

1900s
Democrats = Red
Republican = Blue

[kcguy]

1910 Census
PRESIDENT:  William Taft

Of the existing regions, the 5 largest are (1) CA/NV/WA/OR/ID/MT/WY/ND/SD – 1.71; (2) OH – 1.30; (3) KS/OK/CO/UT – 1.23; (4) TX/NM/AZ – 1.20; and (5) WI/MN – 1.20.

The 5 smallest are (1) GA – 0.71; (2) IL South & West – 0.72; (3) IN – 0.73; (4) MI – 0.76; and (5) AL/FL – 0.79.



SEAT CHANGES:
SHIFT:  The IL South & West region is undersized, so it gains territory from IL Northeast.
SHIFT:  The CA/NV/WA/OR/ID/MT/WY/ND/SD region is oversized.  It gives ND/SD to the IA/NE region.  It also gives NV/ID/MT/WY to the KS/CO/UT portion of the KS/OK/CO/UT region.  The KS/CO/UT portion also gains NM/AZ from the TX/NM/AZ region.  The OK portion of the KS/OK/CO/UT region is added to the AR portion of the TN/AR region.  The TN portion of that region is given to the AL portion of the AL/FL region.  The FL portion is added to GA.

[kcguy]

1910s
Democrats = Red
Republican = Blue

[kcguy]

1920 Census
PRESIDENT:  Woodrow Wilson

Of the existing regions, the 5 largest are (1) OH – 1.36; (2) CA/WA/OR – 1.32; (3) KS/CO/UT/NV/NM/AZ/ID/MT/WY – 1.21; (4) Manhattan/Brooklyn/Bronx – 1.19; and (5) WI/MN – 1.19.

The 5 smallest are (1) IN – 0.69; (2) IL South & West – 0.71; (3) MO – 0.81; (4) IL Northeast – 0.83; and (5) LA/MS – 0.85.



SEAT CHANGES:
LOSS:  The KY/WV region is disbanded.  The KY portion is added to IN.  The WV portion is added to the VA/DC portion of the VA/DC/MD region.  The MD portion is added to the NJ/DE portion of the NY Southeast/NJ/DE region.  The NY portion of the NY Southeast/NJ/DE region is added to the CT/RI portion of the MA South & West/CT/RI region; it also gains the Bronx portion of the Manhattan/Brooklyn/Bronx region and loses territory to the NY Upstate region.  The MA portion of the MA South & West/CT/RI region is added to the NY Northeast/ME/NH/VT region.
SHIFT:  The IL South & West region is undersized, so it gains territory from IL Northeast.
GAIN:  The CA/OR/WA region is split, with the CA/OR portion forming one region.  The WA portion then takes the ID/MT/WY portion of the KS/CO/UT/NV/NM/AZ/ID/MT/WY region, plus the ND/SD portion of the IA/NE/ND/SD region.

[kcguy]

1920s
Democrats = Red
Republican = Blue

[kcguy]

1930 Census
PRESIDENT:  Herbert Hoover

Of the existing regions, the 5 largest are (1) OH – 1.35; (2) CA/OR – 1.35; (3) NY Southeast/CT/RI – 1.21; (4) NJ/DE/MD – 1.20; and (5) MA/ME/NH/VT – 1.20.

The 5 smallest are (1) IL Downstate – 0.68; (2) MO – 0.74; (3) IA/NE – 0.78; (4) LA/MS – 0.84; and (5) WA/ID/MT/WY/ND/SD – 0.84.



SEAT CHANGES:

SHIFT:  The MA/ME/NH/VT region is oversized, so it gives the NH/VT portion to NY Upstate.  NY Upstate gives territory to NY Southeast/CT/RI, which gives territory to Manhattan/Brooklyn.
SHIFT:  IL Downstate is undersized, so it gains territory from the Chicagoland region.
SHIFT:  The CA/OR region is oversized, so the OR portion is added to the WA/MT/ID/WY/ND portion of the WA/MT/ID/WY/ND/SD region.  The SD portion of that region is added to IA/NE.

[kcguy]

1930s
Democrats = Red
Republican = Blue



FUN FACT:  In 1936, the Progressives won the most congressional districts of any party in the WI/MN region, edging out the Farmer-Labor Party.  (For the entire decade, though, the Republican Party won a plurality of seats, far ahead of the second-place Democrats.)

[kcguy]

1940 Census
PRESIDENT:  Franklin Roosevelt

Of the existing regions, the 5 largest are (1) OH – 1.31; (2) CA – 1.31; (3) TX – 1.22; (4) IN/KY – 1.19; and (5) NJ/DE/MD – 1.19.

The 5 smallest are (1) MO – 0.72; (2) non-Cook IL – 0.73; (3) Cook County – 0.77; (4) OK/AR – 0.81; and (5) IA/NE/SD – 0.85.



SEAT CHANGES:

SHIFT:  The MO region is undersized, so it gains KS from the KS/CO/UT/NV/NM/AZ region.  The CO/UT/NV/NM/AZ portion of that region gains NE from the IA/NE/SD region.  The IA portion of the IA/NE/SD region swaps territory with the MN portion of the WI/MN region, with IA/WI forming one new region and MN/SD forming part of another.  The MN/SD portion also gains ND from the WA/OR/ID/MT/WY/ND region.

[kcguy]

1940s
Democrats = Red
Republican = Blue

[kcguy]

1950 Census
PRESIDENT:  Harry Truman

Of the existing regions, the 5 largest are (1) CA – 1.76; (2) OH – 1.32; (3) TX – 1.28; (4) NJ/DE/MD – 1.24; and (5) IN/KY – 1.14.

The 5 smallest are (1) OK/AR – 0.69; (2) non-Cook IL – 0.70; (3) MN/ND/SD – 0.71; (4) Cook County – 0.75; and (5) LA/MS – 0.81.



SEAT CHANGES:

SHIFT:  The NJ/DE/MD region is oversized, so the MD portion is shifted to PA East, and territory is swapped between PA East and PA West.
LOSS:  The non-Cook IL region is eliminated and is divided between the Cook County region and the MO portion of the MO/KS region.  The KS portion is added to the OK/AR region.
SHIFT:  The MN/ND/SD region is undersized, so it gains MT from the WA/OR/ID/WY/MT region.
GAIN:  The CA region is divided in two.

[kcguy]

1950s
Democrats = Red
Republican = Blue

[kcguy]

1960 Census
PRESIDENT:  Dwight Eisenhower

Alaska and Hawaii became states in 1959.  HI is assumed to be part of the CA South region.  AK is assumed to be part of the WA/OR/ID/WY region.

Of the existing regions, the 5 largest are (1) OH – 1.35; (2) TX – 1.34; (3) CA South/HI – 1.25; (4) FL/GA – 1.24; and (5) NY Southeast/CT/RI – 1.16.

The 5 smallest are (1) MN/ND/SD/MT – 0.75; (2) LA/MS – 0.76; (3) WA/OR/ID/WY/AK – 0.81; (4) MA/ME – 0.85; and (5) KS/OK/AR – 0.88.



SEAT CHANGES:

SHIFT:  The NY Southeast/CT/RI region is oversized, so the RI portion is given to the MA/ME region, and part of the NY portion is given to the NY Upstate region.
SHIFT:  The CA South/HI region is oversized, so part of the CA portion is added to CA North, and the HI portion is added to the WA/OR/ID/AK portion of the WA/OR/ID/WY/AK region.  The WY portion of the region is added to the MN/ND/SD/MT region.

[kcguy]

1960s
Democrats = Red
Republican = Blue

[kcguy]

1970 Census
PRESIDENT:  Richard Nixon

Of the existing regions, the 5 largest are (1) FL/GA – 1.40; (2) TX – 1.38; (3) OH – 1.31; (4) CA South Coast – 1.25; and (5) CA North & Southeast – 1.20.

The 5 smallest are (1) LA/MS – 0.72; (2) MN/ND/SD/MT/WY – 0.75; (3) NYC – 0.79; (4) KS/OK/AR – 0.83; and (5) PA West & North – 0.85.



SEAT CHANGES:

SHIFT:  The NYC region is undersized, so it swaps territory with the NY Southeast/CT region.
SHIFT:  The PA West & North region is undersized, so it gains territory from the PA Southeast/MD region.
SHIFT:  The FL/GA region is oversized, so the GA portion is added to the TN portion of the TN/AL region.  The AL portion is added to the LA/MS region.
LOSS:  The IL South/MO region is disbanded.  The IL portion is added to the IL North region.  The MO portion is added to the OK/AR portion of the KS/OK/AR region.  The KS portion is added to the CO/UT/NV/AZ/NM portion of the NE/CO/UT/NV/AZ/NM region.  The NE portion is added to the MN/ND/SD/MT/WY region.
GAIN:  The CA South Coast region is split, with Los Angeles County forming one region and the other region taking parts of the CA North & Southeast region.

[kcguy]

1970s
Democrats = Red
Republican = Blue

[kcguy]

1980 Census
PRESIDENT:  Jimmy Carter

Of the existing regions, the 5 largest are (1) TX – 1.57; (2) KS/CO/UT/NV/AZ/NM – 1.27; (3) IL – 1.26; (4) OH – 1.19; and (5) LA/MS/AL – 1.17.

The 5 smallest are (1) Long Island – 0.78; (2) NY Southeast/CT – 0.79; (3) Los Angeles – 0.83; (4) CA North – 0.83; and (5) WI/IA – 0.84.



SEAT CHANGES:

LOSS:  The NY Southeast/CT region is disbanded, with 3 counties added to the Long Island region and the rest of the region added to the NY portion of the NY Upstate/NH/VT region.  The NH/VT portion is added to the MA/RI/ME region.
LOSS:  The PA Southeast/MD region is disbanded, with the PA portion joining the rest of that state and the MD portion joining the VA/DC portion of the VA/WV/DC region.  The WV portion is added to the IN/KY region.
GAIN:  The KS/CO/UT/NV/AZ/NM region is split, with the KS portion joining the MO portion of the MO/AR/OK region.  The AR/OK portion gains the LA portion of the LA/MS/AL region.  The MS/AL portion trades territory with the GA/TN region, with AL gaining GA and TN gaining MS.
GAIN:  The TX region is split.

[kcguy]

1980s
Democrats = Red
Republican = Blue

[kcguy]

1990 Census
PRESIDENT:  George Bush

Of the existing regions, the 5 largest are (1) FL – 1.30; (2) PA – 1.19; (3) VA/MD/DC – 1.16; (4) CA South – 1.16; and (5) IL – 1.15.

The 5 smallest are (1) TN/MS – 0.75; (2) MO/KS – 0.76; (3) WI/IA – 0.77; (4) TX East – 0.84; and (5) NJ/DE – 0.84.



SEAT CHANGES:

SHIFT:  The WI/IA region is undersized, so it swaps its IA portion for the MN portion of the MN/ND/SD/NE/MT/WY region.  The remainder of the MN/ND/etc region also gains the ID portion of the WA/OR/ID/AK/HI region.
SHIFT:  The MO/KS region is undersized, so it gains the CO portion of the CO/UT/NV/AZ/NM region.
SHIFT:  The CA South region is oversized, so it gives territory to the Los Angeles region.

[kcguy]

1990s
Democrats = Red
Republican = Blue

[kcguy]

2000 Census
PRESIDENT:  Bill Clinton

Of the existing regions, the 5 largest are (1) FL – 1.42; (2) VA/MD/DC – 1.15; (3) CA South – 1.13; (4) GA/AL – 1.12; and (5) MO/CO/KS – 1.12.

The 5 smallest are (1) TN/MS – 0.76; (2) IA/NE/ND/SD/MT/WY/ID – 0.78; (3) NJ/DE – 0.82; (4) MI – 0.88; and (5) Los Angeles – 0.91.



SEAT CHANGES:

GAIN:  The FL region is split in two.
LOSS:  The IA/NE/ND/SD/MT/WY/ID region is disbanded.  The IA portion is added to the WI/MN region, and the ID portion is added to the WA/OR/AK/HI region, with the remainder added to the CO/KS portion of the MO/CO/KS region.  The MO portion is added to the OK/AR portion of the LA/OK/AR region.  The LA portion is added to the TN/MS region.
SHIFT:  To even populations, the CA South and Los Angeles regions swap territory.

[kcguy]

2000s
Democrats = Red
Republican = Blue

[kcguy]

2010 Census
PRESIDENT:  Barack Obama

Of the existing regions, the 5 largest are (1) GA/AL – 1.17; (2) VA/MD/DC – 1.16; (3) WA/OR/ID/AK/HI – 1.15; (4) NC/SC – 1.15; and (5) WI/MN/IA – 1.14.

The 5 smallest are (1) FL South – 0.75; (2) FL North – 0.77; (3) NJ/DE – 0.78; (4) MI – 0.80; and (5) MA/RI/ME/NH/VT – 0.88.

This marks the first census cycle without changes to the map.

[kcguy]

2010s
Democrats = Red
Republican = Blue



This includes predicted results for 2018.

[kcguy]

Also, a final thought:

As I looked through each year’s elections, I realized that my ideas about each region’s voting patterns didn’t quite match reality.  I didn’t realize how late the Democrats’ Southern monopoly started, how long their majority lasted, and just how monopartisan parts of the North were.

So, here I’m cherry-picking some years and showing the number of House seats won by region.  I’m defining DIXIE as AL, AR, FL, GA, LA, MS, NC, SC, TN, & TX, and I’m defining YANKEEDOM as IA, ME, MI, MN, NH, NY (minus the 5 boroughs, Long Island, and Westchester), ND, SD, VT, & WI, since these were the states where I most noticed the patterns.

1882 election
   YANKEEDOM:  40 Republicans, 23 Democrats, and one Greenback
   REMAINDER:  106 Democrats (including Independent Democrats), 73 Republicans (including Independent Republicans), 5 Regulators, and 2 Greenbacks
   DIXIE:  65 Democrats (including Independent Democrats), 8 Republicans, and 2 Independents
1902 election
   YANKEEDOM:  67 Republicans and 5 Democrats
   REMAINDER:  139 Republicans and 87 Democrats
   DIXIE:  86 Democrats and 2 Republicans
1950 election
   YANKEEDOM:  61 Republicans (including Nonpartisan) and 11 Democrats (including DFL)
   REMAINDER:  136 Republicans, 130 Democrats, and one Independent
   DIXIE:  94 Democrats and 2 Republicans
1960 election
   YANKEEDOM:  52 Republicans and 19 Democrats (including DFL)
   REMAINDER:  153 Democrats and 117 Republicans
   DIXIE:  91 Democrats and 5 Republicans
1964 election
   YANKEEDOM:  37 Democrats (including DFL) and 31 Republicans
   REMAINDER:  176 Democrats (including Democrat/Liberal) and 95 Republicans
   DIXIE:  82 Democrats and 14 Republicans
1992 election
   YANKEEDOM:  29 Democrats (including DFL), 27 Republicans, and one Independent
   REMAINDER:  159 Democrats and 105 Republicans
   DIXIE:  70 Democrats and 44 Republicans
1996 election
   YANKEEDOM:  29 Democrats (including DFL), 27 Republicans, and one Independent
   REMAINDER:  133 Republicans, 130 Democrats, and one Independent
   DIXIE:  66 Republicans and 48 Democrats