Complex sentence: The FLDS Church headquarters were originally located in what was then known as Short Creek, Arizona, on the southern border of Utah, which settlement eventually expanded into Utah and became incorporated as the twin municipalities of Hildale, Utah, and Colorado City, Arizona.
Split into simpler sentences: The FLDS Church headquarters were originally located in what was then known as Short Creek, Arizona, on the southern border of Utah. The settlement eventually expanded into Utah and became incorporated as the twin municipalities of Hildale, Utah, and Colorado City, Arizona.