Mississippi Code Title 23. Elections § 23-15-79

(1) Unless the application for registration was made pursuant to Section 23-15-47, the date of registration to vote shall be the date the application for registration to vote was initially received by the registrar or, if submitted by mail, the postmark date, regardless of the date on which the county election commission, circuit court or Supreme Court, as the case may be, makes its final determination allowing the registration.

(2) In the case of an application for registration that has been made pursuant to Section 23-15-47, the date of registration to vote shall be the date the complete and legible application form is received by the county registrar, or, if mailed, the postmark date of the complete and legible application.