Janesville is a city in Black Hawk and Bremer counties in the U.S. state of Iowa.

Janesville was founded in 1849 by John T. Barrick, a Quaker and abolitionist who had relocated to Iowa from Ohio.

According to the book, "The Janesvillians, Volumes I and II" by Maxine Leonard, John T. Barrick built the first mill and frame house in the area.

He platted the town of Janesville, which he named in honor of his wife, Jane McPherson Barrick.

One branch of the tunnel continued northward, connecting to the site of Fort John, a shelter built to protect settlers during the Ho-Chunk uprising in June, 1854.

[7][failed verification] The tunnel terminated in the basement of the home of Abel Crail, who later served in Union Army in the American Civil War, and was the first Commander of Janesville Post No.

According to local legend, the Barricks and other townsfolk sympathetic to their cause aided in the escape of runaway slaves as part of the Underground Railroad.

Slaves were moved through Janesville from Grinnell and continued to Decorah and into southeastern Minnesota.

Due to its proximity to Waterloo-Cedar Falls, the population of Janesville increased to 840 by 1980, when the town was referred to as a "bedroom community".

During the farm crisis and economic recession that hit Northeast Iowa in the 1980s, Janesville's population declined slightly.

New residential subdivisions continue to develop within the city of Janesville and the surrounding area.

The racial makeup of the city was 98.4% White, 0.6% African American, 0.2% Asian, and 0.8% from two or more races.

The Janesville Public Library was created in 1962 with the inspiration of Clark Corwin with help from Hattie Zo Shoesmith and Margaret Theis.

In 1973, the library received a $10,000 (~$52,386 in 2023) grant from the Kinney Lindstrom Foundation that had to be matched by the local public.

Extensive renovations and an addition to the Janesville schools were completed in early 2008, funded by operating surpluses.

[16] Students at Janesville High School can choose to take advanced courses at nearby Waverly-Shell Rock High School in Waverly, the University of Northern Iowa in Cedar Falls, and Hawkeye Community College in Waterloo.