Utah and Idaho are the two most Republican states in the US. In 2000 Utah and Idaho tied in giving George W. Bush the greatest GOP majority. Utah gave him 70.5% and Idaho gave him 69.2%. And previously, Utah gave more votes to Ross Perot than to Bill Clinton!
I believe part of this is due to conservative family values espoused by the LDS church as well as deep patriotism and the church teaching that the US Constitution was inspired by God, so you don’t find the typical liberal belief that the US is the cause of all evil in the world.
However, the political demographics are similar among other western and rural communities in the US which tend to be more conservative, more religious and Christian. And of course there are always exceptions and anomalies. Catholics get to explain Ted Kennedy and John Kerry and Mormons have to explain Harry Reid!