Question

Why did Utah become the center of Mormonism in the USA

Answer 1

Basically when Mormonism was created, it wasn't embraced by those that didn't follow the teachings of Joseph Smith. So the Mormons left and headed out West. At the time, Utah was part of the northern most Mexican territory so it wasn't really in the states. But that's where the Mormons could practice freely and so eventually, Utah became the center for Mormonism in the United States