is a city in Pierce and St. Croix Counties in the U.S. state of Wisconsin. The population was 12,560 at the 2000 census. The city is located mostly within the Town of River Falls in Pierce County; only a small portion lies within the Town of Kinnickinnic in St. Croix County.
River Falls is located 25 miles southeast of downtown St. Paul, Minnesota and is part of the Minneapolis/St. Paul Metropolitan Statistical Area, along with the rest of Pierce and St. Croix Counties.
According to the United States Census Bureau, the city has a total area of 6.56 square miles (17.0 km²). 5.0 square miles (12.9 km²) of it is land and 0.04 square miles (0.1 km²) of it (0.80%) is water.
River Falls lies on the banks of the Kinnickinnic River, a class one trout stream. The Kinnickinnic is broken into two parts, the upper, which begins its run approximately 10 miles north of Interstate 94 and the lower, which runs through a narrow canyon south of town. The two sections are separated by a pair of hydroelectric dams run by River Falls Public Utilities. River Falls is the largest city in Wisconsin that sits on a level 1 trout stream. In addition to the upper and lower Kinnickinnic, the South Fork of the Kinnickinnic River runs through the city, dividing the campus of the University of Wisconsin-River Falls into two sections.