| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 120,119 | 166,261 | 290,672 | |
| 2020 | R | 115,847 | 160,209 | 280,239 | |
| 2016 | R | 91,093 | 137,914 | 244,832 | |
| 2012 | R | 88,481 | 130,669 | 223,351 | |
| 2008 | R | 99,586 | 126,568 | 228,137 | |
| 2004 | R | 74,328 | 145,591 | 221,372 | |
| 2000 | R | 54,968 | 115,900 | 175,367 | |
| 1996 | R | 49,120 | 92,875 | 155,286 | |
| 1992 | R | 44,255 | 88,447 | 160,180 | |
| 1988 | R | 38,982 | 96,979 | 137,029 | |
| 1984 | R | 31,308 | 99,090 | 131,016 | |
| 1980 | R | 30,026 | 79,963 | 118,897 | |
| 1976 | R | 35,533 | 72,106 | 109,676 | |
| 1972 | R | 24,223 | 81,036 | 107,138 | |
| 1968 | R | 29,870 | 69,953 | 108,307 | |
| 1964 | D | 53,041 | 52,243 | 105,508 | |
| 1960 | R | 33,233 | 78,390 | 111,889 | |
| 1956 | R | 26,538 | 69,026 | 95,801 | |
| 1952 | R | 28,146 | 64,193 | 92,721 | |
| 1948 | R | 21,308 | 46,306 | 68,499 | |
| 1944 | R | 27,353 | 44,888 | 72,673 | |
| 1940 | R | 32,210 | 44,939 | 77,418 | |
| 1936 | R | 38,454 | 42,272 | 82,273 | |
| 1932 | R | 24,406 | 34,502 | 61,019 | |
| 1928 | R | 12,146 | 55,530 | 68,192 | |
| 1924 | R | 12,091 | 42,787 | 58,034 | |
| 1920 | R | 9,521 | 29,549 | 40,542 | |
| 1916 | R | 10,016 | 20,292 | 31,996 | |
| 1912 | R | 8,574 | 12,668 | 34,282 | |
| 1908 | R | 8,109 | 23,523 | 32,931 | |
| 1904 | R | 7,092 | 26,083 | 34,077 | |
| 1900 | R | 8,437 | 23,230 | 32,368 | |
| 1896 | R | 8,145 | 24,337 | 33,490 | |
| 1892 | R | 10,326 | 20,126 | 31,222 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Lancaster County's large Plain community — one of the oldest and most populous Amish settlements in the world — shapes both its rural land use and its persistently conservative presidential margins, which held at R+15.9 in 2024 despite statewide competitiveness.
The Republican margin in Lancaster County reached its widest at sixty-four points in 1928. The margin in 2024 was sixteen points, in line with the county's deep historical pattern.
Lancaster County's loyalty is rooted in its place. Median household income of $86,959, a 82% non-Hispanic-white share, and a population of 557,931 together describe a community whose political habits are deeply settled. The county's voting pattern over the last decade is most similar to that of Ottawa County and Dorchester County.