Cedar Falls is a city in Black Hawk County, Iowa, United States. As of the 2020 United States census, the city population was 40,713. Cedar Falls is home to the University of Northern Iowa (UNI), a public university.

Cedar Falls, along with neighboring city Waterloo, Iowa, are the two principal municipalities within the Waterloo-Cedar Falls Metropolitan Statistical Area. The Cedar River traverses the vicinity to the southeast.

Cedar Falls was first settled in March 1845 by brothers-in-law William R. Sturgis and Erasmus D. Adams. Initially, the city was named Sturgis Falls. The city was called Sturgis Falls until it was merged with Cedar City (another city on the other side of the Cedar River), creating Cedar Falls. The city's founders are honored each year with a week-long community-wide celebration named in their honor – the Sturgis Falls Celebration.

Because of the availability of water power, Cedar Falls developed as a milling and industrial center before the Civil War. The establishment of the Civil War Soldiers' Orphans Home in Cedar Falls changed the direction in which the city developed when, following the war, it became the first building on the campus of the Iowa State Normal School (now the University of Northern Iowa).

According to the United States Census Bureau, the city has a total area of 29.61 square miles (76.69 km²), of which 28.75 square miles (74.46 km²) is land and 0.86 square miles (2.23 km²) is water.

Natural forest, prairie and wetland areas are found within the city limits at the Hartman Reserve Nature Center.

Cedar Falls is part of the Waterloo-Cedar Falls metropolitan area.

As of the census of 2020, there were 40,713 people and 15,254 households. The population density was 1,401.8 inhabitants per square mile (541.2 inhabitants/km²). The racial makeup of the city was 91.2% White, 1.3% African American, 0.3% Native American, 4.5% Asian, and 2.5% from two or more races. Hispanic or Latino people of any race were 2.7% of the population.