Largest differences between neighboring counties of various characteristics

[nclib]

I haven't verified these, so please add if you can. So far I have these (Obama margin in first county plus McCain margin (or minus Obama margin) in the second county):

overall:

Shannon, SD and Sheridan, NE 139.21
Hancock and Glascock, GA  132.58
Macon and Elmore, AL 124.98
Orleans and St. Bernard, LA   105.77
Perry and Chilton, AL   102.94
Duval and McMullen, TX   100.31

both majority-white:

Blaine and Cassia, ID 98.64
San Miguel and Dolores, CO 92.43
Blaine and Butte, ID 85.52
Teton, WY and Fremont, ID 85.41
San Miguel and Montrose, CO   85.3
Routt and Rio Blanco, CO 83.49
Summit and Rich, UT 82.62   
Summit and Duchesne, UT 81.1

both counties having at least 100,000 votes:

Orleans/Jefferson, LA 86.90
Prince George's/Anne Arundel, MD 80.29
DeKalb/Gwinnett, GA 68.76
Lexington/Richland, SC 66.95
Milwaukee/Waukesha, WI 61.53
Essex/Morris, NJ 60.61
Salt Lake/Utah, UT 58.99
Los Angeles/Kern, CA 58.12
Philadelphia/Bucks, PA 58.05
Broward/Collier, FL 57.17

[Brittain33]

both counties having at least 100,000 votes:

Orleans/Jefferson, LA 86.90
Prince George's/Anne Arundel, MD 80.29
DeKalb/Gwinnett, GA 68.76
Lexington/Richland, SC 66.95
Milwaukee/Waukesha, WI 61.53
Essex/Morris, NJ 60.61
Salt Lake/Utah, UT 58.99
Cook/McHenry, IL 58.74
Los Angeles/Kern, CA 58.12
Broward/Collier, FL 57.17

[Brittain33]

Cook/McHenry, IL 58.74

Obama won McHenry, so this would be more like 48.

[nclib]

Cook/McHenry, IL 58.74

Obama won McHenry, so this would be more like 48.

My mistake. In that case, it drops off the list.

both counties having at least 100,000 votes:

Orleans/Jefferson, LA 86.90
Prince George's/Anne Arundel, MD 80.29
DeKalb/Gwinnett, GA 68.76
Lexington/Richland, SC 66.95
Milwaukee/Waukesha, WI 61.53
Essex/Morris, NJ 60.61
Salt Lake/Utah, UT 58.99
Cook/McHenry, IL 58.74
Los Angeles/Kern, CA 58.12
Broward/Collier, FL 57.17

I will update that, and I also noticed Philadelphia/Bucks 58.05.

[Filuwaúrdjan]

Try Duval and McMullen in Texas.

[Verily]

Try Duval and McMullen in Texas.

100.31. But they're also beaten by Perry and Chilton Counties, AL, I think.

And Glascock and Hancock Counties, Georgia are 132.58. (Yes, they do share a, very short, border.)

[nclib]

Try Duval and McMullen in Texas.

100.31. But they're also beaten by Perry and Chilton Counties, AL, I think.

And Glascock and Hancock Counties, Georgia are 132.58. (Yes, they do share a, very short, border.)

Perry and Chilton are 102.94.

I've also added to the majority-white list. The Dem county in each case appears to be a ski resort.

[Brittain33]

I've also added to the majority-white list. The Dem county in each case appears to be a ski resort.

We had to get our Obama supplies from relatives in Routt County, Colorado because they didn't waste any on Massachusetts.

[Matt Damon™]

But Why such a difference?

[Filuwaúrdjan]

I was thinking of Hancock-and-Glascock the other day, but couldn't quite tell whether they actually bordered each other or not.

[bgwah]

I've always thought Glascock was interesting. An 84% Republican county surrounded by Democratic counties. Like a white island in a sea of black.

[Verily]

I was thinking of Hancock-and-Glascock the other day, but couldn't quite tell whether they actually bordered each other or not.

I looked up twelve different county maps of Georgia; eight had them unambiguously bordering, and four (including our own) were unclear either way. None had them unambiguously not bordering. And Wikipedia says that they border each other. So I'm satisfied.

And it would be interesting to know the history of why Glascock County ended up overwhelmingly white while its surroundings are demographically mixed (or overwhelmingly black in the case of Hancock).

[Bacon King]

I was thinking of Hancock-and-Glascock the other day, but couldn't quite tell whether they actually bordered each other or not.

I looked up twelve different county maps of Georgia; eight had them unambiguously bordering, and four (including our own) were unclear either way. None had them unambiguously not bordering. And Wikipedia says that they border each other. So I'm satisfied.

And it would be interesting to know the history of why Glascock County ended up overwhelmingly white while its surroundings are demographically mixed (or overwhelmingly black in the case of Hancock).

It's a small county in a region with extreme racial segregation. My guess would be that it's so small that it happens just by chance to encompass a white area without any black areas.

[Filuwaúrdjan]

Might be an environmental factor or something, slightly poorer soil perhaps [qm]

[Matt Damon™]

Might be an environmental factor or something, slightly poorer soil perhaps [qm]

Good explanation for it.

[minionofmidas]

Glascock County was created from the southern portion of Warren (and a tiny bit of Jefferson) in 1857.

Racial and population data for Glascock, Warren, Jefferson, Washington, Hancock 1860ff.

1860
Glascock 2400, 32% Black
Hancock 12000, 68%
Jefferson 10200, 60%
Warren 9800, 56%
Washington 12700, 52%

1870
Glascock 2700, 30%
Hancock 11300, 68%
Jefferson 12200, 65%
Warren 10500, 59%
Washington 15800, 52%

1880
Glascock 3600, 30%
Hancock 17000, 70%
Jefferson 15700, 64%
Warren 10900, 63%
Washington 22000, 57%

As you can see, the pattern's very old (though the Black proportion in Glascock has decreased since). Creation date is a bit too early for racial gerrymandering (during the half-century after the war, county creations in the south were usually done with an eye to racial figures - Long GA was formed from the White part of Black Liberty County. Vance NC was formed from the Blackest parts of its three neighbors to make those - all Black-controlled until then - Democratic-voting), so maybe it really ia a kind of "upland" place as Al guessed.

They have the coolest name for a weekly local rag, btw.