| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 3,700 | 13,677 | 17,602 | |
| 2020 | R | 4,071 | 13,297 | 17,603 | |
| 2016 | R | 3,672 | 12,322 | 16,698 | |
| 2012 | R | 5,022 | 10,402 | 15,719 | |
| 2008 | R | 5,683 | 9,512 | 15,487 | |
| 2004 | R | 6,383 | 9,049 | 15,521 | |
| 2000 | R | 6,203 | 7,294 | 13,761 | |
| 1996 | D | 6,054 | 4,579 | 12,078 | |
| 1992 | D | 6,576 | 4,368 | 12,749 | |
| 1988 | D | 5,888 | 5,256 | 11,171 | |
| 1984 | D | 5,725 | 5,152 | 10,917 | |
| 1980 | D | 6,231 | 4,403 | 10,779 | |
| 1976 | D | 6,906 | 2,578 | 9,614 | |
| 1972 | R | 2,806 | 4,290 | 7,252 | |
| 1968 | D | 3,301 | 2,432 | 7,921 | |
| 1964 | D | 5,968 | 1,679 | 7,668 | |
| 1960 | D | 3,484 | 3,388 | 6,872 | |
| 1956 | D | 4,358 | 2,015 | 6,382 | |
| 1952 | D | 3,445 | 1,474 | 4,934 | |
| 1948 | D | 2,942 | 711 | 3,673 | |
| 1944 | D | 2,947 | 1,316 | 4,274 | |
| 1940 | D | 3,549 | 1,100 | 4,662 | |
| 1936 | D | 3,472 | 1,141 | 4,624 | |
| 1932 | D | 4,246 | 863 | 5,129 | |
| 1928 | D | 2,036 | 1,879 | 3,925 | |
| 1924 | D | 2,752 | 1,192 | 4,010 | |
| 1920 | D | 3,569 | 1,883 | 5,492 | |
| 1916 | D | 2,263 | 1,201 | 3,530 | |
| 1912 | D | 1,675 | 634 | 2,787 | |
| 1908 | D | 1,852 | 1,217 | 3,152 | |
| 1904 | D | 1,587 | 920 | 2,758 | |
| 1900 | D | 1,594 | 997 | 2,735 | |
| 1896 | D | 1,926 | 568 | 2,557 | |
| 1892 | D | 1,081 | 360 | 2,001 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Marshall County, anchored by Benton and framed by Kentucky Lake and Lake Barkley, has shifted decisively rightward over two decades — its 2024 presidential margin of R+56.7 placing it among the commonwealth's most one-sided rural counties.
The unraveling was not abrupt. The Democratic margin in Marshall County peaked at sixty-six points in 1932; it narrowed steadily over the late twentieth century. The 2000 election delivered the county to the Republican party for the first time in many years, by a margin of eight points. By 2024, the margin had widened further.
The economic and demographic context is severe. Marshall County's median household income of $65,831 is among the lowest of any county in the United States; 12% of residents live below the federal poverty line. The county's voting pattern over the last decade is most similar to that of Graves County and Lee County.