| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | D | 62,326 | 16,112 | 80,904 | |
| 2020 | D | 66,240 | 14,544 | 82,508 | |
| 2016 | D | 57,242 | 13,285 | 75,762 | |
| 2012 | D | 52,199 | 20,249 | 73,411 | |
| 2008 | D | 50,473 | 19,181 | 70,364 | |
| 2004 | D | 41,116 | 19,844 | 61,515 | |
| 2000 | D | 33,633 | 19,043 | 55,199 | |
| 1996 | D | 27,968 | 15,554 | 45,399 | |
| 1992 | D | 30,784 | 16,700 | 52,675 | |
| 1988 | D | 24,358 | 20,913 | 45,804 | |
| 1984 | D | 23,552 | 21,166 | 45,253 | |
| 1980 | R | 17,134 | 17,865 | 40,388 | |
| 1976 | D | 19,858 | 16,880 | 37,910 | |
| 1972 | R | 1,431 | 4,553 | 6,156 | |
| 1968 | D | 14,351 | 13,265 | 31,816 | |
| 1964 | R | 2,879 | 2,958 | 5,863 | |
| 1960 | D | 9,662 | 8,826 | 18,551 | |
| 1956 | R | 7,451 | 8,633 | 16,449 | |
| 1952 | R | 6,471 | 8,579 | 15,072 | |
| 1948 | D | 3,917 | 3,903 | 8,707 | |
| 1944 | D | 4,391 | 3,405 | 7,823 | |
| 1940 | D | 4,004 | 1,802 | 5,831 | |
| 1936 | D | 3,381 | 1,225 | 4,650 | |
| 1932 | D | 2,941 | 1,199 | 4,184 | |
| 1928 | R | 1,307 | 1,617 | 2,924 | |
| 1924 | D | 1,136 | 556 | 1,960 | |
| 1920 | D | 1,417 | 921 | 2,379 | |
| 1916 | D | 1,038 | 364 | 1,412 | |
| 1912 | D | 951 | 132 | 1,201 | |
| 1908 | D | 1,218 | 247 | 1,473 | |
| 1904 | D | 738 | 187 | 932 | |
| 1900 | D | 2,003 | 935 | 2,944 | |
| 1896 | D | 1,830 | 1,281 | 3,180 | |
| 1892 | D | 1,982 | 1,162 | 3,163 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
This independent city across the Potomac from Washington, D.C., delivered a 57-point Democratic margin in 2024, driven by a dense, highly educated, and majority-minority electorate concentrated in one of the region's oldest urban cores.
The unraveling was not abrupt. The Democratic margin in Alexandria city peaked at sixty-eight points in 1912; it narrowed steadily over the late twentieth century. The 1984 election delivered the county to the Republican party for the first time in many years, by a margin of five points. By 2024, the margin had widened further.
The economic and demographic context is severe. Alexandria city's median household income of $119,681 is among the lowest of any county in the United States; 8% of residents live below the federal poverty line. The county's voting pattern over the last decade is most similar to that of Arlington County and King County.
