We have Christian polygamists in Lane County, at least two families that I am aware of. To my knowledge, few have been arrested for it and when prosecuted, the rulings were overturned. In 2016 11 Mormon polygamists were arrested, but on charges of food stamp fraud and money laundering. (Civil isn't allowing me to post url's, but the citation is from BBC-Canada) Utah had about 40,000 polygamists in 1998 (Wiki). Polygamy is seldom prosecuted because typically, a family has a single marriage license and additional wives and their children cohabit, which isn't illegal and is difficult to prosecute (ibid).