Alabama’s election map draws a dark curve across the middle of the state. It lies along chalk laid down by a Cretaceous sea, and the links between the two are soil, cotton and slavery.
01 · The rock
A sea left a curve across the South
The same arc shows up in Mississippi, Georgia and the Carolinas, though the soil differs along the way.
In Alabama and Mississippi the cotton belt follows Cretaceous chalk. In Georgia and the Carolinas it runs near the inland edge of the Coastal Plain, on different soils. Cities such as Atlanta add their own dark patches, and the Mississippi Delta is river silt, so geology does not explain every county on this map. Bamberg County, South Carolina, a classic example of the arc, gave the Democrat 57.0% in 2024.
02 · The soil
Chalk weathered into dark, fertile cotton ground
The belt runs about 310 miles and is up to 25 miles wide. Its dark prairie soil is the usual explanation for the name Black Belt, though sources differ.
Booker T. Washington wrote in 1901 that the name first described the soil, and only later the people who were forced to work it.
How one rock leads to one map, link by link
Chalk seafloor
Dark prairie soil
Cotton plantations
Enslaved labor
Black majorities
The 2024 map
Each link is historical. Soil does not cast votes: people do, and these votes reflect who lives here and why.
03 · 1860
Cotton brought slavery to the chalk soil
On the eve of the Civil War, 45.1% of Alabama’s people were enslaved. In Marengo County it was 78.3%; in hilly Winston, 3.4%.
Share of residents enslaved, 1860 census
The ten counties with the most enslaved people held 47% of the state’s total of 435,080. Nine of them are in the bars at left. The tenth is Barbour, with 16,150.
Dallas County alone counted 25,760 enslaved people out of 33,625 residents.
04 · Then and now
160 years later, the pattern has held
Counties with the highest shares of enslaved people in 1860 remain mostly majority-Black today, even after the Great Migration thinned them out.
County
Enslaved 1860
Black 2020
Dem. 2024
Poverty 2023
Marengo
78.3
52.1
47.8
23.5
Dallas
76.6
70.8
65.8
31.4
Greene
76.5
80.7
77.6
31.0
Sumter
75.3
70.9
70.2
33.5
Wilcox
72.3
70.7
65.5
32.7
Lowndes
69.8
73.4
68.4
29.4
Macon
67.8
80.6
77.7
28.8
Montgomery
66.0
59.4
64.5
18.3
Perry
65.7
68.6
71.1
33.8
Bullock
—
72.7
72.6
33.6
Winston
3.4
1.0
7.9
16.6
Alabama
45.1
26.8
34.1
15.7
Bold: the eight counties that lead all three lists in the next section
Hale and Bullock were created after 1860, so Bullock shows no 1860 figure. Greene’s 1860 area was larger than today’s because Hale was cut partly from it. Marengo, the highest in 1860, narrowly went Republican in 2024, with the Democrat at 47.8%.
05 · 2024
Same eight, three lists
Sort Alabama’s 67 counties by Black share, by Democratic vote, or by poverty. The top eight are identical each time. Montgomery, in blue, is ninth for two lists.
Across all 67 counties, Black share and Democratic vote correlate at r = 0.97 (our calculation). Black Alabamians have voted heavily Democratic since the 1960s, so this map mostly charts where they live.
Black share, 2020
Greene80.7
Macon80.6
Lowndes73.4
Bullock72.7
Sumter70.9
Dallas70.8
Wilcox70.7
Perry68.6
Montgomery59.4
Democratic vote, 2024
Macon77.7
Greene77.6
Bullock72.6
Perry71.1
Sumter70.2
Lowndes68.4
Dallas65.8
Wilcox65.5
Montgomery64.5
Poverty, 2023
Perry33.8
Bullock33.6
Sumter33.5
Wilcox32.7
Dallas31.4
Greene31.0
Lowndes29.4
Macon28.8
Conecuh26.5
06 · Stakes
The soil’s fortune ran out long ago
The boll weevil hit in the 1910s and the Great Migration drew people north. Wilcox County has lost 70% of its 1900 population, while Alabama has grown more than 2.7 times.
19 of 24Black Belt counties in persistent poverty, by the University of Alabama’s wider definition.
33.2%poverty among Black residents of the region, against 12% for White residents.
−30%population change in 16 traditional counties from 1910 to 2000, excluding Montgomery. Alabama grew by about 108%.
Wilcox County residents, census counts
Poverty rate 2023, every Alabama county
Model-based estimates. Montgomery, ninth by vote share, has a poverty rate of 18.3%.
What to notice on the map
Read it from north to south
Follow the blue line. It marks the schematic edge of the old sea. The darkest counties lie just south of it, not along today’s coast.
Look at Birmingham. Jefferson is the only county won by the Democrat outside the traditional belt.
Find Selma. The 1965 voting-rights march ran from Selma to Montgomery through the belt’s center, along US 80.
Hold the caveat. Before 1965, many Black Southerners were kept from voting, so the curve looks different on older maps. The geology is ancient, but this political pattern is recent.