The Utah US state is very popular for polygamy thanks to the fact that they have a lot of history dating back few hundreds of years ago when polygamy was widely spread across the territory where Utah is now situated.
Back in the year 1852, The Church of Jesus Christ of Latter-days Saints, which was led by Brigham Young, felt secure enough to announce to the world the fact that they were practicing polygamy in Utah. At the same time the US government threatened them with the legal standing of the church they were running. And the government stated that this practice is not legal and a very large territory from all over the world have renounced on doing it.
Even if one of the largest part of the Mormon population have easily accepted the prohibition of being married to more than one partner, there were still many groups left out of the LDS Church that had absolutely no problem in practicing the plural marriages.
Utah at the same time has a law against cohabitation, and the American Civil Liberties Union of Utah is opposing to that.
The fact that the Utah state has always been one of the places in United States where the polygamy in Utah is still alive is a very well known fact in United States and thanks to that there were a few series that are exploiting that thing. For example there is "Big Love" a series featured on HBO, where the main characters are part of a polygamous family from Utah, living in the first decade of the 21st century. One thing that people find very appealing about this series is the fact that it is able to explore the complex problems that are coming up in a polygamy family in Utah and this means all the legal, moral and religious issues that might occur in a polygamy family are going to be presented.
There is also a reality TV show available on TLC since 2010 called Sister Wives that is going to deal with the polygamy fundamentalist Mormon family where everything is going to happen in the modern day Utah.