Why Mormons founded Utah?
The Mormons went to Utah to avoid persecution by hostile mobs. They had been chased out of almost every city or state they had inhabited or founded. Some had been killed and Missouri even made it legal to kill any Mormon of any age if they didn't leave their property and much of their belongings and leave the state.
Mormons founded hundreds of cities, mostly in the Western US but some in the midwest, Canada, and Mexico. Nearly every city in Utah and most in southern Idaho and northern Arizona were founded by Mormons. Some of the more well-known cities founded by Mormons are Salt Lake City, Utah and Las Vegas, Nevada.
Some say that the Mormons had to denounce polygamy before Utah became a state. This may or may not be true, as the plans to make Utah a state were in action before the Church officially denounced polygamy. Either way, Mormons arrived there in 1847, Utah became a territory in 1850, Mormons ended polygamy in 1890, and Utah became a state in 1896.
When the Mormons first established their settlement in Utah they would be classified a counterculture because of their belief in polygyny?
There are most definitely more members of the Church of Jesus Christ of Latter-day Saints (the "Mormon" church) living in Utah than in Arizona. Membership records released by the Church show that as of January 2013, there were 1,951,937 Mormons living in Utah and 404,261 Mormons living in Arizona... meaning that Utah has four times more Mormons than Arizona does.
Most towns in Utah and southern Idaho were settled by Mormons, as well as many in northern Arizona, western Wyoming, eastern Nevada, California, southern Canada, and northern Mexico. Some of the more well known cities that were founded by Mormons are Salt Lake City, Provo, Ogden, and St. George, Utah; Las Vegas, Nevada; Mesa, Arizona; and Cardston, Alberta.
The first permanent white settlers in Utah arrived in 1847. They were members of the Church of Jesus Christ of Latter-day Saints (commonly called "Mormons"). Between 1847 and 1900, hundreds of thousands of Mormons from all over the United States and the world moved to Utah, where they founded the majority of the cities and towns. By the 1850's, miners, railroad workers, farmers, and merchants of other religions had moved to Utah to find employment.