| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 1,706 | 7,599 | 9,416 | |
| 2020 | R | 1,750 | 6,672 | 8,513 | |
| 2016 | R | 1,569 | 5,171 | 6,955 | |
| 2012 | R | 2,174 | 4,143 | 6,433 | |
| 2008 | R | 2,832 | 4,085 | 7,065 | |
| 2004 | R | 3,445 | 3,685 | 7,173 | |
| 2000 | D | 3,765 | 2,411 | 6,265 | |
| 1996 | D | 3,213 | 1,696 | 5,302 | |
| 1992 | D | 4,382 | 1,714 | 6,722 | |
| 1988 | D | 2,452 | 2,098 | 4,581 | |
| 1984 | D | 2,645 | 2,337 | 5,010 | |
| 1980 | D | 2,948 | 1,841 | 4,868 | |
| 1976 | D | 3,222 | 1,443 | 4,702 | |
| 1972 | R | 1,243 | 2,014 | 3,320 | |
| 1968 | R | 847 | 1,532 | 3,895 | |
| 1964 | D | 2,291 | 1,402 | 3,693 | |
| 1960 | D | 1,547 | 1,440 | 3,026 | |
| 1956 | D | 1,982 | 1,690 | 3,693 | |
| 1952 | D | 1,949 | 1,814 | 3,763 | |
| 1948 | D | 2,412 | 1,751 | 4,412 | |
| 1944 | D | 2,341 | 2,161 | 4,502 | |
| 1940 | D | 2,830 | 2,041 | 4,871 | |
| 1936 | D | 2,947 | 2,140 | 5,105 | |
| 1932 | D | 2,323 | 1,530 | 3,853 | |
| 1928 | R | 1,690 | 2,261 | 3,951 | |
| 1924 | D | 1,829 | 1,406 | 3,257 | |
| 1920 | R | 1,983 | 2,572 | 4,555 | |
| 1916 | D | 1,407 | 1,343 | 2,760 | |
| 1912 | D | 1,394 | 1,219 | 2,880 | |
| 1908 | R | 845 | 958 | 1,803 | |
| 1904 | R | 858 | 921 | 1,781 | |
| 1900 | D | 909 | 890 | 1,799 | |
| 1896 | D | 997 | 890 | 1,889 | |
| 1892 | D | 1,377 | 1,283 | 2,856 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
DeKalb County's R+62.7 margin in 2024 reflects the broader realignment of small, rural Tennessee counties over the past two decades, where Democratic registration once ran deep but presidential-level voting has swung sharply rightward.
The 2004 election was the turning point, when the Republican candidate carried the county by three points. The 2024 margin was sixty-three points, in line with the county's new direction.
The demographics suggest why. A population of 20,959, a 88% non-Hispanic-white share, and a median household income of $53,153 situate the county in the broader realignment patterns of recent cycles. The county's voting pattern over the last decade is most similar to that of Hickman County and Van Buren County.
