| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | D | 228,404 | 168,679 | 404,859 | |
| 2020 | D | 221,846 | 165,459 | 393,746 | |
| 2016 | D | 160,121 | 152,912 | 334,058 | |
| 2012 | R | 133,124 | 171,722 | 310,835 | |
| 2008 | R | 141,216 | 170,957 | 315,444 | |
| 2004 | R | 103,955 | 173,467 | 280,061 | |
| 2000 | R | 86,676 | 140,494 | 235,027 | |
| 1996 | R | 73,750 | 114,188 | 200,573 | |
| 1992 | R | 63,960 | 103,734 | 197,131 | |
| 1988 | R | 39,297 | 106,621 | 146,658 | |
| 1984 | R | 28,414 | 97,429 | 125,843 | |
| 1980 | R | 39,157 | 51,977 | 95,816 | |
| 1976 | D | 45,002 | 34,324 | 79,326 | |
| 1972 | R | 7,688 | 43,977 | 51,665 | |
| 1968 | R | 8,755 | 18,649 | 45,209 | |
| 1964 | R | 16,647 | 20,863 | 37,511 | |
| 1960 | D | 12,906 | 8,240 | 21,146 | |
| 1956 | D | 11,696 | 6,798 | 18,494 | |
| 1952 | D | 10,182 | 4,163 | 14,345 | |
| 1948 | D | 4,766 | 1,524 | 7,098 | |
| 1944 | D | 5,000 | 1,349 | 6,349 | |
| 1940 | D | 4,447 | 992 | 5,448 | |
| 1936 | D | 2,802 | 707 | 3,515 | |
| 1932 | D | 3,079 | 218 | 3,321 | |
| 1928 | R | 1,426 | 1,711 | 3,137 | |
| 1924 | D | 1,360 | 362 | 1,910 | |
| 1920 | D | 1,208 | 1,095 | 2,303 | |
| 1916 | D | 1,750 | 137 | 2,321 | |
| 1912 | D | 1,519 | 41 | 2,005 | |
| 1908 | D | 889 | 548 | 1,630 | |
| 1904 | D | 1,171 | 220 | 1,712 | |
| 1900 | D | 1,156 | 311 | 1,576 | |
| 1896 | D | 1,387 | 758 | 2,238 | |
| 1892 | D | 1,794 | 564 | 2,873 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Cobb County, once a reliably Republican anchor of metro Atlanta, recorded a 14.9-point Democratic margin in 2024, reflecting a college-educated suburban realignment that has reshaped Georgia's competitive statewide map.
The Democratic margin in Cobb County has rarely exceeded eighty-six points in modern history; the Republican margin has rarely exceeded seventy points. 2024 delivered the county to the Democratic candidate by fifteen points.
Cobb County's demographics resemble the country more than they resemble most counties. A 49% non-Hispanic-white share, a 9% poverty rate, and a median household income of $102,738 — all within the broad national range. The county's voting pattern over the last decade is most similar to that of Gwinnett County and Frederick County.
