Bigamy vs. Polygamy

Both bigamy and polygamy are cases of marriage to more then one partner, but this is where the similarity ends. In polygamy, all involved parties are aware of the situation and have agreed to it. In bigamous relationships, parties may be unaware that their partners are married to other people.
Polygamy
The most common form of polygamy is a man married to more than one wife. Polygamous marriages usually result in a single family unit where the spouses in the multiple marriage raise their collective children together. Polygamy is a common practice among many religions of the world, such as Mormons, Buddhists, Muslims and Hindus.
Bigamy
Bigamy also includes an individual with multiple spouses. Again, the most common form is a man with more than one wife. However, the situation is kept secret from the spouses. This means that the individual works to prevent each spouse from finding out about the other ones, while establishing, maintaining and supporting more than one family at a time. Bigamy is a criminal offense; however, cases of accidental bigamy are often dropped. Accidental bigamy happens in rare situations when a divorce is not finalized because of a technicality and when a spouse is believed to have passed.
Both polygamy and bigamy are illegal within the United States. Bigamy was always illegal, and polygamy was ruled illegal in the late 1800s. Despite the fact that it is illegal, polygamy is still practiced among some rare groups like the Mormons and the Buddhists. However, today prosecution rarely occurs in polygamy cases.