| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 5,659 | 10,152 | 16,198 | |
| 2020 | R | 6,541 | 9,773 | 16,734 | |
| 2016 | R | 6,215 | 8,803 | 16,347 | |
| 2012 | D | 10,714 | 7,785 | 18,911 | |
| 2008 | D | 9,821 | 7,062 | 17,224 | |
| 2004 | D | 10,152 | 7,472 | 17,858 | |
| 2000 | D | 9,632 | 6,339 | 16,572 | |
| 1996 | D | 8,831 | 4,932 | 15,662 | |
| 1992 | D | 9,366 | 4,777 | 17,152 | |
| 1988 | D | 10,911 | 6,228 | 17,290 | |
| 1984 | D | 8,912 | 8,756 | 17,809 | |
| 1980 | R | 8,204 | 8,793 | 18,265 | |
| 1976 | D | 9,017 | 8,195 | 17,465 | |
| 1972 | R | 7,510 | 9,748 | 17,618 | |
| 1968 | R | 8,076 | 8,883 | 18,036 | |
| 1964 | D | 12,244 | 6,321 | 18,582 | |
| 1960 | R | 9,936 | 10,765 | 20,701 | |
| 1956 | R | 8,226 | 11,571 | 19,829 | |
| 1952 | R | 8,625 | 12,289 | 20,969 | |
| 1948 | D | 9,201 | 7,801 | 17,212 | |
| 1944 | R | 8,252 | 9,406 | 17,736 | |
| 1940 | R | 9,117 | 10,616 | 19,766 | |
| 1936 | D | 9,630 | 8,955 | 19,317 | |
| 1932 | D | 10,624 | 7,084 | 17,902 | |
| 1928 | R | 7,785 | 11,645 | 19,455 | |
| 1924 | R | 4,903 | 9,999 | 18,377 | |
| 1920 | R | 5,177 | 10,763 | 16,323 | |
| 1916 | R | 3,993 | 4,395 | 8,587 | |
| 1912 | D | 3,891 | 2,016 | 8,520 | |
| 1908 | D | 4,706 | 4,262 | 9,144 | |
| 1904 | R | 3,848 | 4,612 | 8,749 | |
| 1900 | D | 5,182 | 4,486 | 9,778 | |
| 1896 | D | 5,153 | 4,847 | 10,162 | |
| 1892 | D | 4,956 | 3,971 | 9,137 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Lee County sits at Iowa's southeastern tip along the Mississippi, anchoring a working-class industrial corridor that has moved decisively toward Republican presidential candidates over the past four election cycles, widening from a near-toss-up to a 28-point margin by 2024.
The county's recent history is a story of close margins. The Democratic margin reached thirty-two points in 1964; the Republican margin reached thirty-four points in 1920. Most other elections have been decided by single-digit points.
Lee County's demographics — a population of 32,893, a 91% non-Hispanic-white share, a median household income of $62,382 — 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 Wapello County and Bay County.