The Tuscobia Winter Ultra is a human powered run, bike or ski event held on the Tuscobia and Wild Rivers State Trails in Northern Wisconsin, in the middle of winter.

There are two options: an 80-mile one-way route or a 160-mile out and back. The 160-mile requires completion of a qualifying event, and is itself a qualifier for the Iditarod Trail Invitational.

Both distances have required gear and are largely self-supported, with minimal checkpoint support. No outside help is allowed from family, friends, or random strangers. Patronizing local businesses is encouraged: this means buying a soda or a burger, while taking a break; this does not mean drying out all your gear, using the restroom, filling your water, and taking off without spending a cent.

As in life, respect and common sense go a long way in this event.