Janesville is the county seat of Rock county, and is distant from Milwaukee about 65 miles, from Beloit 13, and from Madison 41. This town has a valuable water power, created by dams constructed across the river. The growth of this town has been very rapid. In 1843, it contained only 333 souls, and in 1853 it contained a population of 5000. A number of rail roads pass through this town, which will soon raise it to importance, and make it a point of considerable resort. It has 2 foundries, 1 mill for manufacturing water-lime, 1 oil mill, 1 woolen factory, 3 saw mills, 4 flouring mills, 4 newspapers, 6 churches, 3 banks, male and female academies, an institution tor the blind, a mill for sawing stone and turning wood. It has also a large brewery and distillery, both in very high repute for the excellence of the beverages manufactured in them. These are the property of Mr. BUNSTER, who also has established a bank at Janesville, which is said to be conducted on liberal principles.