The following info comes from VoteSmart.org.
DEADLINE IS OCTOBER 1
OBTAINING A VOTER REGISTRATION FORM
In person voter registration is available at the office of the county Circuit Clerk or Municipal. Voter registration is also available when applying for or renewing your driver's license, or when applying for services at numerous state and federal government agencies.
Voter registration can also be done by mail. For a mail-in application, call your county election office or pick one up at the courthouse, public library or other participating government office. Mail-in voter registration forms are also available from the Secretary of State's Office.
Obtain a voter registration application online here.
MISSISSIPPI ABSENTEE BALLOTS
Who Can Absentee Vote in Mississippi?
Some registered voters are eligible to vote absentee because of age, health or work demands, or their affiliation with the U.S. armed forces. For example, voters who will be outside their county of residence on election day are entitled to vote by absentee ballot. Please check with your Circuit or Municipal Clerk to determine if you are entitled to vote absentee and to learn the procedures for doing so. (contact information)
Additional Information for Overseas Voters
Source of information:
First Floor, Heber Ladner Building
401 Mississippi Street
Jackson, Mississippi 39201
Elections Hotline: 800-829-6786