| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | D | 222,280 | 66,480 | 299,193 | |
| 2020 | D | 270,522 | 58,613 | 337,240 | |
| 2016 | D | 245,751 | 50,421 | 317,207 | |
| 2012 | D | 223,896 | 59,999 | 289,098 | |
| 2008 | D | 207,127 | 57,194 | 269,221 | |
| 2004 | D | 182,592 | 54,923 | 240,645 | |
| 2000 | D | 154,888 | 44,441 | 217,000 | |
| 1996 | D | 145,586 | 39,753 | 199,392 | |
| 1992 | D | 132,921 | 51,378 | 219,273 | |
| 1988 | D | 143,677 | 77,137 | 224,410 | |
| 1984 | D | 152,568 | 91,563 | 244,997 | |
| 1980 | D | 113,416 | 73,271 | 216,207 | |
| 1976 | D | 142,010 | 80,623 | 232,372 | |
| 1972 | D | 166,250 | 85,272 | 252,821 | |
| 1968 | D | 203,406 | 48,952 | 268,977 | |
| 1964 | D | 257,161 | 40,251 | 298,254 | |
| 1960 | D | 252,823 | 85,750 | 339,617 | |
| 1956 | D | 191,245 | 162,836 | 355,686 | |
| 1952 | D | 240,957 | 162,147 | 404,879 | |
| 1948 | D | 265,611 | 105,671 | 385,067 | |
| 1944 | D | 234,475 | 139,285 | 374,487 | |
| 1940 | D | 243,233 | 138,575 | 384,145 | |
| 1936 | D | 223,732 | 96,418 | 350,010 | |
| 1932 | D | 198,792 | 88,737 | 296,072 | |
| 1928 | D | 204,603 | 99,392 | 306,130 | |
| 1924 | R | 78,702 | 104,658 | 221,993 | |
| 1920 | R | 67,552 | 108,089 | 186,098 | |
| 1916 | D | 61,047 | 42,492 | 106,148 | |
| 1912 | D | 46,059 | 24,179 | 97,851 | |
| 1908 | R | 43,773 | 46,337 | 95,539 | |
| 1904 | D | 51,714 | 43,681 | 98,964 | |
| 1900 | D | 47,534 | 40,951 | 91,365 | |
| 1896 | R | 31,744 | 53,633 | 89,551 | |
| 1892 | D | 44,504 | 35,304 | 81,392 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Suffolk County is among the most Democratic jurisdictions in the country, anchored by Boston's dense urban electorate and large student and immigrant populations that have produced presidential margins exceeding 50 points in recent cycles.
The Democratic margin in Suffolk County reached its widest at seventy-three points in 1964. The margin in 2024 was fifty-two points — still decisive.
Suffolk County's loyalty is rooted in its place. Median household income of $95,631, a 46% non-Hispanic-white share, and a population of 785,121 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 Orleans Parish and Philadelphia County.
