State primaries vary from state to state. These dates are tentative and subject to change. For update information, go the the Federal Election Commission.
| STATE | PRIMARY DATE | CAUCUS DATE |
| Alabama | February 5, 2008 | n/a |
| Alaska | n/a | February 5, 2008 |
| American Samoa | n/a | February 23, 2008 (R) March 10, 2008 (D) |
| Arizona | February 5, 2008 | n/a |
| Arkansas | February 5, 2008 | n/a |
| California | February 5, 2008 | n/a |
| Colorado | n/a | February 5, 2008 |
| Connecticut | February 5, 2008 | n/a |
| Delaware | February 5, 2008 | n/a |
| D.C. | February 12, 2008 | n/a |
| Florida | January 29, 2008 | n/a |
| Georgia | February 5, 2008 | n/a |
| Guam | n/a | February 16, 2008 (R) May 3, 2008 (D) |
| Hawaii | n/a | February 19, 2008 (D) March 2, 2008 (R) |
| Idaho | May 27, 2008 | February 5, 2008 (D) |
| Illinois | February 5, 2008 | n/a |
| Indiana | May 6, 2008 | n/a |
| Iowa | n/a | January 3, 2008 (R) January 3, 2008 (D) |
| Kansas | n/a | February 5, 2008 (D) February 9, 2008 (R) |
| Kentucky | May 20, 2008 | n/a |
| Louisiana | February 9, 2008 | n/a |
| Maine | n/a | February 1, 2008 (R) February 10, 2008 (D) |
| Maryland | February 12, 2008 | n/a |
| Massachusetts | March 4, 2008 | n/a |
| Michigan | January 15, 2008 | n/a |
| Minnesota | n/a | February 5, 2008 |
| Mississippi | March 11, 2008 | n/a |
| Missouri | February 5, 2008 | n/a |
| Montana | June 3, 2008 | n/a |
| Nebraska | May 13, 2008 | February 9, 2008 (D) |
| Nevada | n/a | January 19, 2008 |
| New Hampshire | January 8, 2008 | n/a |
| New Jersey | February 5, 2008 | n/a |
| New Mexico | June 3, 2008 (R) | February 5, 2008 (D) |
| New York | February 5, 2008 | n/a |
| North Carolina | May 6, 2008 | n/a |
| North Dakota | n/a | February 5, 2008 |
| Ohio | March 4, 2008 | n/a |
| Oklahoma | February 5, 2008 | n/a |
| Oregon | May 20, 2008 | n/a |
| Pennsylvania | April 22, 2008 | n/a |
| Puerto Rico | February 24, 2008 (R) June 1, 2008 (D) | n/a |
| Rhode Island | March 4, 2008 | n/a |
| South Carolina | January 19, 2008 (R) January 29, 2008 (D) | n/a |
| South Dakota | June 3, 2008 | n/a |
| Tennessee | February 5, 2008 | n/a |
| Texas | March 4, 2008 | n/a |
| Utah | February 5, 2008 | n/a |
| Vermont | March 4, 2008 | n/a |
| Virginia | February 12, 2008 | n/a |
| Virgin Islands | n/a | February 9, 2008 (D) February 23, 2008 (R) |
| Washington | February 19, 2008 | April 28, 2008 (D) |
| West Virginia | May 13, 2008 | n/a |
| Wisconsin | February 19, 2008 | n/a |
| Wyoming | n/a | January 5, 2008 (R) March 8, 2008 (D) |
Source: Federal Election Commission |
- More from Campaign 2008
