| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 18,092 | 43,542 | 62,513 | |
| 2020 | R | 16,412 | 36,726 | 54,029 | |
| 2016 | R | 9,655 | 28,451 | 40,180 | |
| 2012 | R | 8,120 | 27,113 | 35,764 | |
| 2008 | R | 8,492 | 23,300 | 32,066 | |
| 2004 | R | 5,320 | 20,120 | 25,581 | |
| 2000 | R | 3,642 | 13,666 | 17,652 | |
| 1996 | R | 3,289 | 8,319 | 12,796 | |
| 1992 | R | 2,397 | 6,427 | 13,269 | |
| 1988 | R | 2,659 | 7,214 | 9,939 | |
| 1984 | R | 1,639 | 6,688 | 8,349 | |
| 1980 | R | 1,985 | 4,036 | 6,184 | |
| 1976 | R | 1,828 | 2,087 | 3,936 | |
| 1972 | R | 610 | 1,890 | 2,518 | |
| 1968 | D | 778 | 614 | 1,975 | |
| 1964 | D | 1,305 | 445 | 1,755 | |
| 1960 | D | 917 | 652 | 1,583 | |
| 1956 | D | 920 | 657 | 1,583 | |
| 1952 | D | 1,175 | 602 | 1,785 | |
| 1948 | D | 947 | 117 | 1,252 | |
| 1944 | D | 1,153 | 98 | 1,358 | |
| 1940 | D | 1,510 | 95 | 1,605 | |
| 1936 | D | 1,168 | 26 | 1,195 | |
| 1932 | D | 1,237 | 62 | 1,299 | |
| 1928 | D | 850 | 289 | 1,139 | |
| 1924 | D | 1,371 | 93 | 1,471 | |
| 1920 | D | 873 | 104 | 994 | |
| 1916 | D | 828 | 27 | 872 | |
| 1912 | D | 642 | 0 | 670 | |
| 1908 | — | — | — | — | |
| 1904 | — | — | — | — | |
| 1900 | — | — | — | — | |
| 1896 | — | — | — | — | |
| 1892 | — | — | — | — | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Rockwall is Texas's smallest county by area, yet its fast-growing suburban and exurban population consistently delivers lopsided Republican margins — hitting R+40.9 in 2024 — making it a reliable anchor in northeast Dallas's exurban ring.
The unraveling was not abrupt. The Democratic margin in Rockwall County peaked at ninety-six points in 1912; it narrowed steadily over the late twentieth century. The 1972 election delivered the county to the Republican party for the first time in many years, by a margin of fifty-one points. By 2024, the margin had widened further.
The economic and demographic context is severe. Rockwall County's median household income of $127,981 is among the lowest of any county in the United States; 4% of residents live below the federal poverty line. The county's voting pattern over the last decade is most similar to that of Comal County and Lubbock County.