| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 67,456 | 68,866 | 137,979 | |
| 2020 | D | 68,286 | 66,869 | 137,083 | |
| 2016 | R | 58,112 | 60,069 | 125,129 | |
| 2012 | D | 68,036 | 49,025 | 119,114 | |
| 2008 | D | 75,775 | 50,351 | 127,691 | |
| 2004 | D | 67,921 | 57,372 | 125,898 | |
| 2000 | D | 59,399 | 49,027 | 112,335 | |
| 1996 | D | 57,508 | 39,884 | 108,791 | |
| 1992 | D | 56,381 | 39,283 | 117,804 | |
| 1988 | D | 53,913 | 48,306 | 103,300 | |
| 1984 | R | 52,471 | 55,860 | 109,266 | |
| 1980 | R | 45,946 | 48,918 | 103,162 | |
| 1976 | D | 55,385 | 49,641 | 107,439 | |
| 1972 | R | 42,022 | 61,542 | 105,713 | |
| 1968 | D | 51,604 | 43,134 | 99,847 | |
| 1964 | D | 72,944 | 31,393 | 104,886 | |
| 1960 | D | 53,723 | 51,525 | 105,543 | |
| 1956 | R | 33,802 | 54,430 | 88,555 | |
| 1952 | R | 36,619 | 48,836 | 85,846 | |
| 1948 | R | 28,159 | 33,806 | 63,245 | |
| 1944 | R | 32,912 | 35,247 | 68,578 | |
| 1940 | R | 31,735 | 36,608 | 68,714 | |
| 1936 | D | 33,042 | 25,607 | 65,355 | |
| 1932 | D | 19,592 | 18,371 | 40,442 | |
| 1928 | R | 19,278 | 30,542 | 50,097 | |
| 1924 | R | 3,502 | 19,480 | 31,784 | |
| 1920 | R | 6,311 | 19,465 | 30,569 | |
| 1916 | D | 9,641 | 8,933 | 20,630 | |
| 1912 | D | 5,633 | 4,958 | 18,408 | |
| 1908 | R | 6,173 | 10,828 | 19,419 | |
| 1904 | R | 5,119 | 11,951 | 19,018 | |
| 1900 | R | 7,281 | 11,816 | 20,207 | |
| 1896 | R | 9,210 | 11,819 | 21,592 | |
| 1892 | R | 7,589 | 8,918 | 17,923 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Erie County tracked the national mood almost exactly in 2024, landing within a point of even after swinging from Obama to Trump to Biden and back. Its blend of post-industrial Rust Belt workers and mid-sized city voters makes it one of Pennsylvania's closest-watched counties.
The county's recent history is a story of close margins. The Democratic margin reached forty points in 1964; the Republican margin reached fifty points in 1924. Most other elections have been decided by single-digit points.
Erie County's demographics — a population of 269,052, a 83% non-Hispanic-white share, a median household income of $63,354 — 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 Saginaw County and Lake County.