| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | D | 11,265 | 7,699 | 19,167 | |
| 2020 | D | 13,138 | 6,194 | 19,581 | |
| 2016 | D | 11,690 | 3,897 | 16,433 | |
| 2012 | D | 9,486 | 4,235 | 13,911 | |
| 2008 | D | 8,683 | 4,518 | 13,303 | |
| 2004 | D | 6,909 | 4,668 | 11,689 | |
| 2000 | D | 5,233 | 3,344 | 8,893 | |
| 1996 | D | 5,241 | 2,256 | 8,167 | |
| 1992 | D | 3,512 | 3,024 | 8,080 | |
| 1988 | R | 3,268 | 3,320 | 6,690 | |
| 1984 | R | 2,463 | 3,855 | 6,389 | |
| 1980 | R | 2,089 | 2,674 | 5,340 | |
| 1976 | R | 2,265 | 2,312 | 4,738 | |
| 1972 | R | 1,866 | 2,137 | 4,079 | |
| 1968 | R | 1,557 | 1,702 | 3,533 | |
| 1964 | D | 1,955 | 1,503 | 3,460 | |
| 1960 | D | 1,868 | 1,265 | 3,135 | |
| 1956 | R | 1,131 | 1,646 | 2,778 | |
| 1952 | R | 1,365 | 1,716 | 3,081 | |
| 1948 | D | 1,424 | 1,058 | 2,519 | |
| 1944 | D | 1,291 | 727 | 2,022 | |
| 1940 | D | 1,536 | 978 | 2,516 | |
| 1936 | D | 1,729 | 742 | 2,530 | |
| 1932 | D | 1,606 | 625 | 2,260 | |
| 1928 | D | 962 | 919 | 1,884 | |
| 1924 | D | 673 | 579 | 1,450 | |
| 1920 | R | 706 | 850 | 1,556 | |
| 1916 | D | 726 | 666 | 1,442 | |
| 1912 | D | 250 | 56 | 469 | |
| 1908 | — | — | — | — | |
| 1904 | — | — | — | — | |
| 1900 | — | — | — | — | |
| 1896 | — | — | — | — | |
| 1892 | — | — | — | — | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Santa Cruz sits on Arizona's southern border with Nogales as its seat, and its heavily Hispanic population has delivered Democratic presidential margins above 15 points in each of the last several cycles, making it one of the state's most consistently blue counties.
The Democratic margin in Santa Cruz County peaked at forty-seven points in 2016. By 1992 the county had flipped, voting Republican for the first time in many years. The 2024 margin was nineteen points, the most Democratic-leaning result in the county's modern history.
The economic context is the key. Santa Cruz County's median household income of $55,217 sits well below state and national norms, and 20% of residents live below the federal poverty line. The shift here is part of a broader realignment of working-class places across the country. The county's voting pattern over the last decade is most similar to that of El Paso County and Hudson County.