| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | D | 2,165 | 813 | 3,023 | |
| 2020 | D | 2,718 | 835 | 3,593 | |
| 2016 | D | 2,735 | 789 | 3,592 | |
| 2012 | D | 3,297 | 838 | 4,163 | |
| 2008 | D | 3,029 | 947 | 4,024 | |
| 2004 | D | 2,565 | 985 | 3,591 | |
| 2000 | D | 2,338 | 967 | 3,340 | |
| 1996 | D | 2,222 | 941 | 3,273 | |
| 1992 | D | 2,159 | 1,049 | 3,455 | |
| 1988 | D | 1,796 | 1,295 | 3,114 | |
| 1984 | D | 2,170 | 1,570 | 3,769 | |
| 1980 | D | 2,778 | 1,182 | 3,990 | |
| 1976 | D | 2,634 | 1,064 | 3,709 | |
| 1972 | R | 1,386 | 1,741 | 3,146 | |
| 1968 | D | 1,538 | 997 | 3,355 | |
| 1964 | R | 772 | 1,740 | 2,512 | |
| 1960 | R | 583 | 888 | 1,471 | |
| 1956 | D | 380 | 262 | 1,317 | |
| 1952 | R | 440 | 751 | 1,191 | |
| 1948 | D | 55 | 14 | 1,110 | |
| 1944 | D | 678 | 8 | 718 | |
| 1940 | D | 905 | 30 | 935 | |
| 1936 | D | 1,236 | 0 | 1,239 | |
| 1932 | D | 1,108 | 0 | 1,118 | |
| 1928 | D | 816 | 24 | 840 | |
| 1924 | D | 450 | 14 | 464 | |
| 1920 | D | 440 | 11 | 451 | |
| 1916 | — | — | — | — | |
| 1912 | — | — | — | — | |
| 1908 | — | — | — | — | |
| 1904 | — | — | — | — | |
| 1900 | — | — | — | — | |
| 1896 | — | — | — | — | |
| 1892 | — | — | — | — | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Allendale's electorate is roughly 75% Black, making it a consistent outlier among South Carolina's rural counties, which trend heavily Republican — its D+44.7 margin in 2024 reflects that demographic concentration rather than any urban influence.
The unraveling was not abrupt. The Democratic margin in Allendale County peaked at 100 points in 1936; it narrowed steadily over the late twentieth century. The 1976 election delivered the county to the Republican party for the first time in many years, by a margin of forty-two points. By 2024, the margin had widened further.
The economic and demographic context is severe. Allendale County's median household income of $32,328 is among the lowest of any county in the United States; 28% of residents live below the federal poverty line. The county's voting pattern over the last decade is most similar to that of Noxubee County and Petersburg city.