Janesville owes its existence to its location at a waterpower site in the midst of one of the richest agricultural regions in North America. The nine-foot fall of the Rock River through the city gave Janesville's founders the power to run the mills that established an industrial and commercial base for the community.
Just as important as the water in the Rock River was the wealth of the farmland on its banks. On the northern edge of the great Midwestern tall grass prairie, Rock County has been one of Wisconsin's leading agricultural producers since settlement. One pioneer described the Rock Prairie without “the mark of the plow” in 1836 as “the paradise of the West.” So attractive was its soil that between 1840 and 1850, county population grew from about 1,700 to nearly 21,000. It was not exactly the California gold rush, but similar in that newcomers flocked to the county to exploit the natural wealth of its soil.
A good share of the prairie's original wealth was transferred to Janesville in return for the services its people supplied to the farmers. First, they milled, bought, sold and shipped prairie wheat. They imported and sold manufactured goods to the farmers and provided credit, legal, educational, entertainment, cultural and information services. Janesville the industrial city was also Janesville the farm service city and the first service delivered was at the grain mills on the Rock. It is no accident that the first Wisconsin state fair was held in Janesville in 1851. It was the ideal place to exhibit the agricultural prowess and promise of the state, much of which came from Rock County.
The tie to the fertile ground around Janesville predates settlement, of course. The Rock River Valley was home to mound builders who first shaped the earth into animal effigies and other forms before the Christian era. Their presence further illustrates the natural wealth of the region. People who are living a hand-to-mouth existence are not able to take time away from subsistence labor to erect monuments, be they stone temples in Mexico or turtle mounds in the Rock Valley--nor are they likely to have the cultural motivations to build for reasons other than shelter.
By the time Europeans arrived in Wisconsin, the mound builders were long gone and the people usually identified as their successors were on the verge of dying out. The upheavals of the fur trade era were a demographic disaster for the Ho-Chunk, Ottawa, Potawatomi, Sauk, Fox and other tribes who lived in Southern Wisconsin prior to settlement. Their significance to Janesville lies in the cession of their land at several treaty sessions dating back as early as 1804, thereby allowing non-Indian Americans to claim the ground. The Ho-Chunk signed off in 1829 and 1832. The Sauk and Fox signed away their rights to the Rock River Valley in 1804, but a faction of these tribes, led by the Sauk leader Black Sparrow Hawk, refused to accept the agreement. In 1832, when settlers and soldiers arrived at Black Hawk's village at the mouth of Rock River in Illinois in order to compel the Indians to move across the Mississippi, Black Hawk resisted.
Several "firsters" (as in "first" to settle) staked claims in what became Janesville and a handful were already onsite when Henry Janes hiked west across the prairie from Racine in the winter of 1835-1836. He scouted up and down the river valley from Lake Kegonsa to Beloit and west into the lead mining region, before claiming a quarter section, 160 acres, on the river in what became the east side of Janesville. He hired two frontiersmen to build him a log cabin and headed back to Racine where he stayed until May, when he and his family returned and moved into their new home. Janes drew up a plat map and began to sell city lots, even though his own claim to the land had yet to be accepted by the federal government.Though called a war, the Black Hawk affair was actually the retreat of the Indians up the Rock and then west across Wisconsin and their pursuit by United States, Illinois and Michigan/Wisconsin soldiers and volunteers, including the young Abe Lincoln. One of the Indian camp sites was at Janesville. The pursuit of Black Hawk's band inevitably ended badly for the Indians, as the soldiers caught up with them as they attempted to cross the Mississippi near Bad Axe in Vernon County. In addition to removing the Indians who might have been an obstacle to settlement, the Black Hawk War introduced southern Wisconsin to the rest of the United States. In 1833, the southern tier of counties was surveyed and the most opportunistic denizens of the frontier began to scout the territory.
United States mail service also began that year, which meant the village had to be officially christened. Janes later wrote that he asked the postmaster general to name the place Black Hawk, in honor of the Sauk chief. The postmaster general said that title was already taken and decreed that the post office, and therefore the village, would be known as Janesville.The Wisconsin territorial legislature organized Rock County that year and Janes immediately began to lobby the lawmakers for an exclusive charter to run a ferry across the Rock and to name the village he platted as the county seat. County seat politicking on the frontier, with rival villages vying to get a leg up on their neighbors, was always contentious and occasionally violent. Herein lies the root of Janesville's rivalry with Beloit, which actually stood little chance of becoming the capital because it was on the county border, and the state legislature almost always awarded the prize to a centrally-located community. Such was the case in Rock County where, in 1837, an unnamed site fitting the legal description of Janes' plat was designated the county seat.
In 1843, A. Hyatt Smith, a well-fixed and accomplished man of affairs public and private, organized a company that obtained a legislative charter to build a dam across the Rock and develop the water power. Two years later, Smith and another set of partners started building "the big mill" on Milwaukee street. When it began operations in 1847, the big mill stood four stories high, and had six "run" of stone to process wheat into fine flour. On opening day, farmers brought grain from as far as fifty miles north and half the city's people turned out to see the turning stones grind wheat into flour.
In 1853, the city government was incorporated, Hyatt Smith was elected its first mayor and Janesville had a population of 4,800. Along the Rock stood four flouring mills, three sawmills, one woolen mill, plus mills to process cement and plaster, work stone and wood. All this and the water power was "only partially developed." In addition, federal surveyors had identified the Rock as one of three rivers in Wisconsin and Illinois that could be "improved" to provide a canal connecting Lake Michigan and the Mississippi River. However, technology was already making canals obsolete, as evidenced in Janesville. One railroad was already in town, another was on its way, and so was Janesville.