| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 14,872 | 75,168 | 90,840 | |
| 2020 | R | 13,017 | 62,045 | 76,128 | |
| 2016 | R | 8,344 | 46,473 | 56,817 | |
| 2012 | R | 7,853 | 39,243 | 47,694 | |
| 2008 | R | 10,502 | 36,974 | 47,951 | |
| 2004 | R | 8,966 | 31,795 | 40,957 | |
| 2000 | R | 8,878 | 23,651 | 33,225 | |
| 1996 | R | 9,447 | 14,580 | 26,855 | |
| 1992 | R | 7,934 | 10,321 | 27,494 | |
| 1988 | R | 8,517 | 14,090 | 22,723 | |
| 1984 | R | 6,050 | 13,647 | 19,759 | |
| 1980 | R | 7,336 | 8,505 | 16,155 | |
| 1976 | D | 8,186 | 4,692 | 12,969 | |
| 1972 | R | 3,184 | 7,152 | 10,349 | |
| 1968 | D | 4,301 | 3,068 | 9,303 | |
| 1964 | D | 5,270 | 2,175 | 7,458 | |
| 1960 | D | 3,629 | 3,467 | 7,148 | |
| 1956 | R | 3,165 | 3,390 | 6,588 | |
| 1952 | R | 3,434 | 3,523 | 6,976 | |
| 1948 | D | 3,061 | 806 | 4,080 | |
| 1944 | D | 3,503 | 559 | 4,555 | |
| 1940 | D | 3,687 | 558 | 4,253 | |
| 1936 | D | 2,493 | 375 | 2,896 | |
| 1932 | D | 3,074 | 372 | 3,482 | |
| 1928 | R | 1,110 | 2,178 | 3,288 | |
| 1924 | D | 2,391 | 438 | 2,979 | |
| 1920 | D | 1,765 | 488 | 2,369 | |
| 1916 | D | 1,797 | 173 | 2,227 | |
| 1912 | D | 1,700 | 135 | 2,406 | |
| 1908 | — | — | — | — | |
| 1904 | — | — | — | — | |
| 1900 | — | — | — | — | |
| 1896 | — | — | — | — | |
| 1892 | — | — | — | — | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Parker County's exurban and rural mix produced an R+66.4 margin in 2024, placing it among the state's most consistently one-sided presidential results despite its proximity to the Dallas–Fort Worth metroplex.
The unraveling was not abrupt. The Democratic margin in Parker County peaked at seventy-eight points in 1932; it narrowed steadily over the late twentieth century. The 1980 election delivered the county to the Republican party for the first time in many years, by a margin of seven points. By 2024, the margin had widened further.
The economic and demographic context is severe. Parker County's median household income of $104,443 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 Hood County and Brown County.