| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 5,426 | 6,134 | 11,665 | |
| 2020 | D | 6,470 | 6,250 | 12,883 | |
| 2016 | D | 6,741 | 6,103 | 12,982 | |
| 2012 | D | 7,749 | 6,282 | 14,123 | |
| 2008 | D | 7,710 | 6,701 | 14,502 | |
| 2004 | R | 4,961 | 6,374 | 11,393 | |
| 2000 | R | 4,845 | 5,643 | 10,587 | |
| 1996 | D | 4,415 | 4,138 | 8,950 | |
| 1992 | R | 4,397 | 4,600 | 9,449 | |
| 1988 | R | 4,175 | 5,100 | 9,334 | |
| 1984 | R | 4,591 | 5,806 | 10,416 | |
| 1980 | D | 5,517 | 4,461 | 10,140 | |
| 1976 | D | 4,267 | 4,108 | 8,646 | |
| 1972 | R | 1,803 | 5,498 | 7,520 | |
| 1968 | D | 2,724 | 704 | 8,379 | |
| 1964 | R | 239 | 4,506 | 4,745 | |
| 1960 | D | 896 | 761 | 3,614 | |
| 1956 | D | 1,270 | 387 | 2,304 | |
| 1952 | D | 2,050 | 1,527 | 3,577 | |
| 1948 | D | 89 | 19 | 2,631 | |
| 1944 | D | 2,409 | 85 | 2,494 | |
| 1940 | D | 2,335 | 49 | 2,384 | |
| 1936 | D | 2,397 | 45 | 2,443 | |
| 1932 | D | 2,371 | 28 | 2,403 | |
| 1928 | D | 2,733 | 161 | 2,894 | |
| 1924 | D | 2,087 | 43 | 2,130 | |
| 1920 | D | 1,300 | 60 | 1,374 | |
| 1916 | D | 1,486 | 20 | 1,513 | |
| 1912 | D | 1,234 | 10 | 1,302 | |
| 1908 | — | — | — | — | |
| 1904 | — | — | — | — | |
| 1900 | D | 1,314 | 54 | 1,416 | |
| 1896 | D | 1,588 | 63 | 1,674 | |
| 1892 | D | 1,041 | 17 | 1,594 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Copiah County's population is roughly 55% Black, yet it returned an R+6.1 presidential margin in 2024 — a combination that makes it a closely watched indicator of realignment patterns in southwest Mississippi's rural electorate.
The Democratic margin in Copiah County has rarely exceeded ninety-eight points in modern history; the Republican margin has rarely exceeded ninety points. 2024 delivered the county to the Republican candidate by six points.
Copiah County's demographics resemble the country more than they resemble most counties. A 43% non-Hispanic-white share, a 23% poverty rate, and a median household income of $49,089 — all within the broad national range. The county's voting pattern over the last decade is most similar to that of Pike County and Yazoo County.