| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 7,376 | 10,696 | 18,276 | |
| 2020 | R | 8,602 | 10,440 | 19,283 | |
| 2016 | R | 7,627 | 9,091 | 17,251 | |
| 2012 | D | 8,475 | 8,443 | 17,086 | |
| 2008 | D | 8,616 | 8,525 | 17,321 | |
| 2004 | R | 6,699 | 7,264 | 14,106 | |
| 2000 | R | 6,449 | 6,767 | 13,390 | |
| 1996 | D | 5,329 | 4,462 | 10,401 | |
| 1992 | D | 5,455 | 4,545 | 11,314 | |
| 1988 | R | 4,508 | 4,962 | 9,547 | |
| 1984 | R | 4,910 | 6,200 | 11,145 | |
| 1980 | D | 5,745 | 4,719 | 10,543 | |
| 1976 | D | 5,134 | 3,324 | 8,522 | |
| 1972 | R | 2,376 | 5,723 | 8,233 | |
| 1968 | R | 2,651 | 2,824 | 8,145 | |
| 1964 | R | 2,051 | 4,637 | 6,688 | |
| 1960 | R | 1,962 | 2,521 | 4,483 | |
| 1956 | D | 1,463 | 635 | 4,048 | |
| 1952 | R | 1,905 | 2,760 | 4,665 | |
| 1948 | D | 223 | 39 | 2,599 | |
| 1944 | D | 1,653 | 45 | 1,997 | |
| 1940 | D | 1,197 | 65 | 1,262 | |
| 1936 | D | 1,463 | 0 | 1,471 | |
| 1932 | D | 1,908 | 0 | 1,914 | |
| 1928 | D | 1,122 | 22 | 1,145 | |
| 1924 | D | 800 | 11 | 813 | |
| 1920 | D | 990 | 15 | 1,005 | |
| 1916 | D | 974 | 31 | 1,006 | |
| 1912 | D | 797 | 0 | 823 | |
| 1908 | D | 1,399 | 91 | 1,490 | |
| 1904 | D | 1,421 | 131 | 1,552 | |
| 1900 | D | 889 | 121 | 1,010 | |
| 1896 | D | 1,646 | 343 | 1,995 | |
| 1892 | D | 1,312 | 472 | 1,784 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Colleton sits in South Carolina's coastal plain, where a predominantly rural economy and a population split almost evenly by race has produced shifting but consistently competitive statewide margins, even as the 2024 presidential result landed at R+18.2.
The county's recent history is a story of close margins. The Democratic margin reached 100 points in 1932; the Republican margin reached forty-one points in 1972. Most other elections have been decided by single-digit points.
Colleton County's demographics — a population of 38,783, a 57% non-Hispanic-white share, a median household income of $51,114 — situate the county close to national averages on several dimensions. The county's voting pattern over the last decade is most similar to that of Chesterfield County and Chowan County.
