State law dictates the requirements for signing a prenuptial agreement. Some states require witnesses, others do not. Here are the states that require witnesses to a prenuptial agreement: Alabama, Arkansas, Florida, Georgia, Louisiana, Maryland, Michigan, Minnesota, New Mexico, and South Carolina.
Here is a list of the number of witnesses required for each state and the statute or legal reasoning for each:
Alabama (2 witnesses) (Practitioner guides and commentary indicate that witnessing is highly recommended, but it is not a statutory requirement in Maryland, though HelloPrenup does require it).
Arkansas (2 witnesses) (Arkansas Code Title 9. Family Law § 9-11-402)
Florida (2 witnesses) (Florida Statute §732.702 (Fla. Stat. § 732.702)
Georgia (2 witnesses) (GA Code § 19-3-62)
Louisiana (2 witnesses) (Louisiana Civil Code Article 2331; Louisiana Civil Code Article 1833)
Maryland (2 witnesses) (Practitioner guides and commentary indicate that witnessing is highly recommended, but it is not a statutory requirement in Maryland, though HelloPrenup does require it).
Michigan (2 witnesses) (Practitioner guides and commentary indicate that witnessing is highly recommended, but it is not a statutory requirement in Maryland, though HelloPrenup does require it).
Minnesota (2 witnesses) (Minnesota Statutes § 519.11, subdivision 2)
New Mexico (2 witnesses) (Practitioner guides and commentary indicate that witnessing is highly recommended, but it is not a statutory requirement in Maryland, though HelloPrenup does require it)
South Carolina (2 witnesses) (Practitioner guides and commentary indicate that witnessing is highly recommended, but it is not a statutory requirement in Maryland, though HelloPrenup does require it).