I've gotten a couple questions in the last few weeks about doing a canoe trip over winter on the Wisconsin River. The first thought to mind is usually "good luck with that." In reality, it is possible, but you've really got to know what you're doing. As far as the Wisconsin River is concerned, the majority of the river is frozen over throughout the winter months, but there is a small section you could feasibly canoe or kayak starting just below the dam at the head of the Lower Wisconsin in Prairie Du Sac.
The constant high water flows keep the ice somewhat at bay allowing you to get maybe a few miles depending on the time of year and recent temperatures, however you absolutely do not want to get caught in a remote stretch of river (and there are a lot of them) when water comes to ice and it's too thick to paddle through and too thin to walk on. Combine that with moving water that's constantly trying to push you downstream and you've got a pretty solid chance of disaster. Basically, it's something to be avoided for the vast majority of people.
That said, there is one slice of winter paddling heaven nearby that is a local favorite for those of us that just need to get our paddles wet no matter the time of year. That place is Lake Columbia, a year round 70 degree hot spot of open water and thick fog that serves as the cooling pond for the Portage power plant. It's small, but it's ice free, and the fog is pretty cool to paddle through.
