Spanish Fork is a city in Utah County, Utah, United States. It is part of the Provo–Orem Metropolitan Statistical Area. The 2020 census reported a population of 42,602. Spanish Fork is the 20th largest city in Utah based on official 2017 estimates from the US Census Bureau. Spanish Fork lies in the Utah Valley, with the Wasatch Range to the east and Utah Lake to the northwest. I-15 passes the northwest side of the city.