| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 18,010 | 25,919 | 44,168 | |
| 2020 | R | 19,361 | 24,608 | 44,800 | |
| 2016 | R | 16,488 | 19,942 | 39,158 | |
| 2012 | D | 21,353 | 15,138 | 37,191 | |
| 2008 | D | 23,706 | 16,956 | 41,326 | |
| 2004 | D | 22,857 | 18,029 | 41,761 | |
| 2000 | D | 21,386 | 16,449 | 39,786 | |
| 1996 | D | 21,798 | 10,827 | 38,477 | |
| 1992 | D | 18,197 | 13,901 | 42,317 | |
| 1988 | R | 18,921 | 20,290 | 39,481 | |
| 1984 | R | 15,963 | 26,062 | 42,149 | |
| 1980 | R | 17,006 | 18,437 | 39,624 | |
| 1976 | R | 17,503 | 22,249 | 39,934 | |
| 1972 | R | 15,286 | 26,145 | 41,503 | |
| 1968 | R | 15,662 | 20,982 | 37,933 | |
| 1964 | D | 29,173 | 12,102 | 41,307 | |
| 1960 | R | 19,430 | 25,848 | 45,302 | |
| 1956 | R | 10,892 | 31,897 | 42,789 | |
| 1952 | R | 13,000 | 28,036 | 41,087 | |
| 1948 | R | 13,200 | 21,160 | 34,925 | |
| 1944 | R | 15,223 | 21,919 | 37,219 | |
| 1940 | R | 15,569 | 24,339 | 39,990 | |
| 1936 | R | 12,763 | 26,031 | 39,556 | |
| 1932 | R | 12,687 | 22,650 | 35,680 | |
| 1928 | R | 12,567 | 25,804 | 38,960 | |
| 1924 | R | 7,026 | 17,682 | 26,856 | |
| 1920 | R | 7,213 | 24,651 | 32,606 | |
| 1916 | R | 6,056 | 13,142 | 19,683 | |
| 1912 | R | 5,329 | 8,404 | 18,721 | |
| 1908 | R | 5,898 | 14,151 | 20,849 | |
| 1904 | R | 5,798 | 15,274 | 21,686 | |
| 1900 | R | 5,699 | 15,296 | 21,539 | |
| 1896 | R | 5,749 | 15,287 | 21,541 | |
| 1892 | R | 6,156 | 13,177 | 20,535 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
St. Lawrence spans more than 2,800 square miles along the Canadian border, and its mix of rural towns, a small college city in Canton, and a declining manufacturing base has driven a steady shift from competitive to reliably Republican in presidential contests.
The Democratic margin in St. Lawrence County has rarely exceeded forty-one points in modern history; the Republican margin has rarely exceeded fifty-three points. 2024 delivered the county to the Republican candidate by eighteen points.
St. Lawrence County's demographics resemble the country more than they resemble most counties. A 92% non-Hispanic-white share, a 17% poverty rate, and a median household income of $62,850 — all within the broad national range. The county's voting pattern over the last decade is most similar to that of Northeastern Connecticut Planning Region and Oxford County.
