St. Croix State Park Professional Review and Guide
"I’ll be honest with you—this wasn’t my favorite ride. The park itself is a beautiful place for camping, hiking, canoeing, even biking on the 5+ miles of paved trails. This featured route is a multi-use trail (part of the Willard Munger State Trail), which in theory is a great idea. But you will discover very rapidly that the trail was not initially intended, and is not currently maintained for, riding a bicycle. Horses use this path, too, and while I like a good horse as much as the next guy, the aftermath of their passing bodes ill for a mountain bike.
This is snowmobile country, and the trail traces through swamps and bogs and other unfriendly places for fat tires. Don’t go that way. The entire portion of the Munger Trail through the park is open for mountain biking, in addition to the paved trails. You may find an area you like at the west end of the park. Tread: A mix of dirt and grass doubletrack."