Lehi (pronounce /ˈliːhаɪ/) is a city in Utah County, Utah, United States. It is named after Lehi, a prophet in the Book of Mormon. As of the 2000 census, the city population was 19,028. A 2006 estimate placed its population at 36,021, making it one of the fastest-growing cities in the state. The center of population of Utah is located in Lehi .