This abandoned railway started out as the Cazenovia and Sauk City Railroad, which built a line between La Valle and Cazenovia, Wisconsin, in 1909. (The C&SC was actually a reorganization of a previously-failed railroad, the Lone Rock-La Valle Railroad, which was incorporated in 1904 but dissolved by 1907 without having laid any track.) The purpose of the line was to connect the Chicago and North Western mainline at La Valle with ports along the Wisconsin River to the south (namely Lone Rock by the LR-LV, and Sauk City by the C&SC). Construction started in La Valle, but only reached as far as Cazenovia, 5 miles away.
The railroad was renamed to the Cazenovia Southern Railroad in 1913.
In July of 1935, a number of bridges along the route were severely damaged by floods, effectively severing the CSRR. As happens so often with other short line railroads that encounter the same predicament, the bridges were too costly to repair, and the CSRR abandoned the line in its entirety in 1937.
Today, Wisconsin Route 58 lies atop a majority of the abandoned grade.