| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 5,153 | 13,142 | 18,468 | |
| 2020 | R | 5,876 | 12,039 | 18,138 | |
| 2016 | R | 4,651 | 8,618 | 13,673 | |
| 2012 | R | 5,133 | 7,461 | 12,721 | |
| 2008 | R | 4,415 | 5,462 | 9,938 | |
| 2004 | R | 4,421 | 7,635 | 12,116 | |
| 2000 | R | 4,322 | 6,231 | 10,746 | |
| 1996 | D | 4,259 | 4,102 | 9,254 | |
| 1992 | R | 3,766 | 3,806 | 9,658 | |
| 1988 | R | 4,657 | 4,777 | 9,504 | |
| 1984 | R | 3,547 | 5,279 | 8,845 | |
| 1980 | R | 3,980 | 4,364 | 8,469 | |
| 1976 | D | 4,565 | 2,415 | 7,072 | |
| 1972 | R | 1,804 | 3,400 | 5,208 | |
| 1968 | D | 2,522 | 1,805 | 5,098 | |
| 1964 | D | 3,224 | 1,283 | 4,516 | |
| 1960 | D | 2,544 | 1,812 | 4,361 | |
| 1956 | R | 1,492 | 1,804 | 3,307 | |
| 1952 | R | 2,124 | 2,147 | 4,281 | |
| 1948 | D | 1,895 | 704 | 2,732 | |
| 1944 | D | 1,757 | 685 | 2,646 | |
| 1940 | D | 1,922 | 418 | 2,344 | |
| 1936 | D | 2,041 | 285 | 2,350 | |
| 1932 | D | 2,101 | 192 | 2,307 | |
| 1928 | R | 682 | 888 | 1,570 | |
| 1924 | D | 869 | 303 | 1,389 | |
| 1920 | D | 531 | 185 | 767 | |
| 1916 | D | 635 | 119 | 810 | |
| 1912 | D | 593 | 34 | 775 | |
| 1908 | — | — | — | — | |
| 1904 | — | — | — | — | |
| 1900 | — | — | — | — | |
| 1896 | — | — | — | — | |
| 1892 | — | — | — | — | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Atascosa County, anchored by Jourdanton along the state's brush-country belt, has shifted decisively rightward over the past decade despite a majority-Hispanic population — a pattern mirroring several neighboring South Texas counties in recent cycles.
The unraveling was not abrupt. The Democratic margin in Atascosa County peaked at eighty-three points in 1932; it narrowed steadily over the late twentieth century. The 2000 election delivered the county to the Republican party for the first time in many years, by a margin of eighteen points. By 2024, the margin had widened further.
The economic and demographic context is severe. Atascosa County's median household income of $70,770 is among the lowest of any county in the United States; 16% of residents live below the federal poverty line. The county's voting pattern over the last decade is most similar to that of Karnes County and Refugio County.