Bigamy is the act of marrying one person while being legally married to another. Polygamy is the practice or custom (often religious) of having more than one wife or husband at a time. Most states prohibit a party from having more than one marriage license at a time, and in most states bigamy is a crime.
In Missouri, bigamy is prohibited under state law. According to Missouri Statutes, Section 568.010, a person commits the offense of bigamy if, while married, he or she purports to marry another person or cohabits with another person in this state under the appearance of being married. Bigamy in Missouri is classified as a Class E felony, which carries potential penalties including fines and imprisonment. Polygamy, which involves having more than one spouse simultaneously, is also not legally recognized in Missouri and falls under the prohibition against bigamy. The state's stance reflects the general position in the United States, where bigamy and polygamy are illegal under both state and federal laws.