It is illegal to marry your first cousin in Louisiana. Louisiana law prohibits marriage between “collateral relations within the fourth degree,” a category that includes first cousins. This restriction is a blanket ban, with no exceptions based on age or other criteria, and has been in place since legislation was introduced in 1902 specifically targeting first cousin marriages.
Marriages between more distant relatives, such as first cousins once removed, second cousins, and beyond, are allowed within the state. The “fourth degree” language refers to the method used to determine familial relationships, and first cousins fall directly under its prohibition.
While Louisiana strictly prohibits first cousin marriages performed within its borders, the situation regarding recognition of such marriages from other jurisdictions is less clear. In at least one case, the Louisiana Court of Appeal recognized a first cousin marriage conducted in Iran after an initial refusal by a lower court, indicating that foreign marriages may be recognized unless they violate a “strong public policy” of the state.
Louisiana does not criminalize sexual relationships or cohabitation between first cousins, but marriage is not permitted. If you are seeking to marry a more distant cousin, such as a first cousin once removed or second cousin, this is allowed in Louisiana, but first cousins are banned from marrying.
You cannot legally marry your first cousin in Louisiana under current law. Marriages to more distant cousins are permitted, and first cousin marriages conducted elsewhere may be recognized in limited circumstances, but generally are not valid if performed in the state.
Sources
[1] https://dataminingdna.com/can-first-cousins-marry-in-louisiana/
[2] https://www.reddit.com/r/coolguides/comments/wg6h3q/a_map_of_where_it_is_legal_to_marry_your_first/
[3] https://conflictoflaws.net/2008/ghassemi-v-ghassemi-an-interesting-decision-from-the-louisiana-court-of-appeal/?print=print
[4] https://en.wikipedia.org/wiki/Cousin_marriage_law_in_the_United_States
[5] https://www.legalmatch.com/law-library/article/cousin-marriage-laws.html
