Rock Falls is a town in Lincoln County, Wisconsin, United States. The population was 618 at the 2010 census. Rock Falls is in central Lincoln County, 11 miles north Merrill, the county seat, and 12 miles south of Tomahawk. U.S. Route 51 crosses part of the eastern side of the town, and Wisconsin Highway 107 crosses the entire town from south to no…Rock Falls is a town in Lincoln County, Wisconsin, United States. The population was 618 at the 2010 census. Rock Falls is in central Lincoln County, 11 miles north Merrill, the county seat, and 12 miles south of Tomahawk. U.S. Route 51 crosses part of the eastern side of the town, and Wisconsin Highway 107 crosses the entire town from south to north, running up the east side of the Wisconsin River.