Fresno is a city in the San Joaquin Valley of California, United States. It is the county seat of Fresno County and the largest city in the greater Central Valley region, as well as the most populated city in Central California. It covers about 114.7 square miles (297 km2) and had a population of 542,107 as of the 2020 census, making it the fifth-most populous city in California, the most populous inland city in California, and the 33rd-most populous city in the nation.