| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | D | 78,327 | 69,474 | 150,081 | |
| 2020 | D | 78,983 | 66,408 | 147,368 | |
| 2016 | D | 64,706 | 60,863 | 131,783 | |
| 2012 | D | 64,965 | 57,450 | 124,301 | |
| 2008 | D | 69,975 | 58,238 | 129,529 | |
| 2004 | R | 55,299 | 65,296 | 121,208 | |
| 2000 | R | 44,390 | 53,631 | 100,658 | |
| 1996 | R | 40,936 | 44,417 | 92,971 | |
| 1992 | R | 36,990 | 45,479 | 98,910 | |
| 1988 | R | 35,079 | 48,917 | 84,677 | |
| 1984 | R | 33,576 | 54,330 | 88,658 | |
| 1980 | R | 27,252 | 44,039 | 78,387 | |
| 1976 | R | 34,342 | 46,819 | 83,122 | |
| 1972 | R | 22,587 | 54,307 | 78,270 | |
| 1968 | R | 25,480 | 48,394 | 81,788 | |
| 1964 | D | 46,119 | 42,718 | 89,431 | |
| 1960 | R | 33,962 | 61,726 | 96,115 | |
| 1956 | R | 29,226 | 61,342 | 90,943 | |
| 1952 | R | 30,985 | 58,385 | 89,656 | |
| 1948 | R | 27,729 | 46,861 | 75,386 | |
| 1944 | R | 30,684 | 44,725 | 75,742 | |
| 1940 | R | 38,305 | 42,394 | 80,981 | |
| 1936 | D | 43,256 | 39,598 | 83,498 | |
| 1932 | R | 22,412 | 36,278 | 60,152 | |
| 1928 | R | 9,115 | 49,108 | 58,617 | |
| 1924 | R | 9,004 | 27,838 | 40,916 | |
| 1920 | R | 11,990 | 26,094 | 39,923 | |
| 1916 | R | 11,483 | 13,954 | 26,752 | |
| 1912 | D | 7,470 | 6,012 | 25,819 | |
| 1908 | R | 7,546 | 15,637 | 24,671 | |
| 1904 | R | 5,040 | 16,508 | 22,734 | |
| 1900 | R | 7,390 | 14,673 | 22,846 | |
| 1896 | R | 6,584 | 14,752 | 22,069 | |
| 1892 | R | 7,520 | 11,010 | 19,157 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Harrisburg anchors Dauphin County's Democratic lean, but surrounding townships keep margins tight — the county voted D+5.9 in 2024, a narrower gap than many mid-size Pennsylvania counties with comparable urban cores.
The county's recent history is a story of close margins. The Democratic margin reached nine points in 2008; the Republican margin reached sixty-eight points in 1928. Most other elections have been decided by single-digit points.
Dauphin County's demographics — a population of 289,593, a 63% non-Hispanic-white share, a median household income of $76,242 — 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 Hopewell city and Kane County.
