| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 2,673 | 2,856 | 5,563 | |
| 2020 | D | 3,108 | 2,441 | 5,590 | |
| 2016 | D | 3,422 | 1,547 | 5,095 | |
| 2012 | D | 3,600 | 1,416 | 5,064 | |
| 2008 | D | 3,409 | 1,456 | 4,903 | |
| 2004 | D | 2,734 | 2,209 | 4,962 | |
| 2000 | D | 3,218 | 1,789 | 5,062 | |
| 1996 | D | 3,789 | 1,332 | 5,411 | |
| 1992 | D | 3,359 | 1,490 | 5,510 | |
| 1988 | D | 3,165 | 1,750 | 4,940 | |
| 1984 | D | 3,037 | 2,340 | 5,391 | |
| 1980 | D | 3,047 | 1,995 | 5,108 | |
| 1976 | D | 2,984 | 1,542 | 4,557 | |
| 1972 | R | 1,384 | 2,317 | 3,730 | |
| 1968 | D | 1,930 | 1,243 | 3,638 | |
| 1964 | D | 2,152 | 1,230 | 3,388 | |
| 1960 | D | 2,109 | 1,367 | 3,487 | |
| 1956 | R | 1,261 | 1,656 | 2,948 | |
| 1952 | R | 1,324 | 2,244 | 3,574 | |
| 1948 | D | 1,139 | 676 | 1,924 | |
| 1944 | D | 846 | 754 | 1,737 | |
| 1940 | D | 1,173 | 740 | 1,920 | |
| 1936 | D | 1,002 | 376 | 1,399 | |
| 1932 | D | 1,042 | 259 | 1,302 | |
| 1928 | D | 396 | 389 | 785 | |
| 1924 | D | 307 | 110 | 434 | |
| 1920 | D | 53 | 9 | 62 | |
| 1916 | D | 110 | 10 | 120 | |
| 1912 | D | 102 | 5 | 107 | |
| 1908 | — | — | — | — | |
| 1904 | — | — | — | — | |
| 1900 | — | — | — | — | |
| 1896 | — | — | — | — | |
| 1892 | — | — | — | — | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Willacy County, anchored by Raymondville and sitting along the Gulf coastal plain, backed Democratic presidential candidates by double digits as recently as 2016 before narrowing to R+3.3 in 2024—one of the starkest swings among majority-Hispanic counties in the Rio Grande Valley.
The Democratic margin in Willacy County peaked at ninety-one points in 1912. By 2024 the county had flipped, voting Republican for the first time in many years. The 2024 margin was three points, the most Republican-leaning result in the county's modern history.
The economic context is the key. Willacy County's median household income of $54,180 sits well below state and national norms, and 24% 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 Hidalgo County and Maverick County.