Lehi is a city in Utah County, Utah, United States. The population was 75,907 at the 2020 census, up from 47,407 in 2010, and it is the cent…Lehi is a city in Utah County, Utah, United States. The population was 75,907 at the 2020 census, up from 47,407 in 2010, and it is the center of population of Utah. The rapid growth in Lehi is due, in part, to the rapid development of the tech industry region known as Silicon Slopes.