The area that became Janesville was the site of a Ho-Chunk village named Įnį poroporo (Round Rock) up to the time of Euro-American settlement.

Following the Indian Removal Act of 1830 and the Black Hawk War of 1832, both nations were forced to surrender this land to the United States.

[9] Later that year, one key settler, Henry F. Janes,[1] a native of Virginia who was a self-proclaimed woodsman and early city planner, arrived in what is now Rock County.

Janes initially wanted to name the budding village "Blackhawk," after the famous Sauk leader, Chief Black Hawk, but was turned down by Post Office officials.

[10] Despite being named after a Virginian, Janesville was founded by old stock Yankee immigrants, descended from the English Puritans who settled New England in the 1600s.

[11][12][13][14] Land surveys encouraged pioneers to settle in the area among the abundance of fertile farmland and woodlands.

Some of the key settlers hailed from the burned-over district of western New York State, (an area notable for being a part of the Christian revival movement known as the Second Great Awakening).

Tallman came to the area in 1850 and bought up large tracts of land in hopes of inspiring his fellow New Yorkers to settle in the fertile Rock County.

One of the crowning moments in Tallman's life was when he convinced the up-and-coming Illinois Republican, Abraham Lincoln, to speak in Janesville in 1859.

As the population grew in the Janesville area, several new industries began cropping up along the Rock River, including flour and lumber mills.

[10] Thomas H. Ruger, of Janesville, served in the war, along with his brothers, Edward, William, and Henry, and he rose to the rank of brigadier general.

[15] After the Civil War, Janesville's agriculture continued to surge and a greater demand for new farming technology led to the development of several foundries and farm machine manufacturers in the area, including the Janesville Machine Company, and the Rock River Iron Works.

With the boom in the farm service sector and establishment of a rail system, Janesville soon began to ship goods to and from prominent eastern cities, including New York, Boston, and Philadelphia.

Farmers responded to this by planting tobacco, which became one of the most profitable and prolific crops grown in Wisconsin during the late 19th century.

In the late 1880s, German immigrants began to arrive in Janesville in large numbers (making up less than 5% of the town before this time).

Janesville's founding English-Puritan-descended Yankee population welcomed them with open arms, with many writing back to relatives in Germany enthusiastically.

[17] In the late 19th and early 20th centuries, the Milwaukee Road and Chicago and North Western railroads had freight and passenger rail connections to the city.

The plant was initially established to produce Samson tractors, a company acquired by GM co-founder William C. Durant.

In the years following World War I, the demand for tractors plummeted and the plant shifted its focus to the production of automobiles.

A Parker pen was used by Dwight D. Eisenhower to sign Germany's Armistice agreement to end World War II in Europe, and subsequently General Douglas MacArthur used his 20-year-old Parker Duofold in the signing of Japan's surrender at the end of the War in the Pacific.

[19] A tree that once stood in downtown Courthouse Park was the site of a lynch mob that, on their second attempt, having been rebuffed by an opposing crowd the day before, hanged a convicted murderer in 1859.

Nowadays the city is the first choice, i.e. Dfa for Köppen classification where the hot season may not be so comfortable at times, although surges in the outskirts without UHI are in the Dfb zone.

The remaining two Janesville parishes are St. John Vianney, located on East Racine Street, and St. William on the near west side.

The Seventh Day Baptist General Conference has its offices in Janesville; the denomination's nearest church is in nearby Milton.

[35] Businesses headquartered in Janesville include Impact Confections, a candy maker; Blain's Farm & Fleet, a four-state retail chain; Woodman's Markets, a regional supermarket chain that built its first store in Janesville; Swing'n'Slide, a maker of wood-and-plastic playground equipment; Hufcor (formerly Hough Shade Company), a manufacturer of room dividers that markets internationally; and Gray's Brewing, maker of boutique beers and soft drinks.

It assembled light-duty trucks and sport utility vehicles,[36] which declined in popularity as gasoline prices increased.

The site of the former Janesville Oasis, known for Bessie, a large fiberglass cow at its entrance, began redevelopment in 2007; the anchor tenant is a Super Menards.

[42][43] As of 2015, the largest employers in the city were:[44] The 1857 Lincoln-Tallman House, which models the Italian Villa-style architecture, is one of 34 sites on the Register.

[56] Janesville also has a nearly 500-acre greenbelt system to provide areas for surface water runoff and habitat for a diversity of plants and animals.

Janesville is served by Southern Wisconsin Regional Airport (KJVL), which provides general aviation and air cargo services.