Jefferson is a city situated in the state of Iowa, United States. It serves as the county seat of Greene County and is positioned along the North Raccoon River. As of the 2020 census, the city had a population of 4,182 residents.
The town is bisected from east to west by the historic Lincoln Highway, while U.S. Route 30 is located approximately one mile to the north. A notable local landmark is the Mahanay Memorial Bell Tower, which stands 168 feet tall on the town square and is visible for miles. The tower was named in honor of Floyd Mahanay, a former resident who was known as a philanthropist and businessman.