Nephi is a city in Juab County, Utah, United States. It is part of the Provo–Orem, Utah Metropolitan Statistical Area. The population was 4,733 at the 2000 census. It is the county seat of Juab County. It was settled by Mormon pioneers in 1851, and is the principal city in Juab Valley, an agricultural area. Nephi was named after Nephi, son of Lehi from the Book of Mormon. According to the United States Census Bureau, the city has a total area of 4.2 square miles (10.8 km²), all of it land.

In the U.S. state of Utah, Interstate 15 runs north–south through the southwestern and central portions of the state, passing through many of the population centers of that state, including St. George, Provo, Salt Lake City, and Ogden, the latter three being part of the urban area known as the Wasatch Front. It is the primary north–south highway in Utah, as the majority of the state's population lives along its corridor.