From the Minnesota Department of Natural Resources web site:
The 135 mile Arrowhead State Trail extends from the intersection with the Taconite State Trail (near Tower) to 3 miles south of International Falls. The natural surface trail is used primarily for snowmobiling. Approximately 69 miles of the trail are suitable for horseback riding, mountain biking and hiking in the summer, however there may be wet areas.
The trail is relatively flat between International Falls and the Ash River. This northern portion of the trail goes through a number of areas that have standing water in the summer which makes this section of the trail mostly suited to winter use.
The southern part of the Arrowhead is very different from the northern part. It features rolling hills with numerous lakes and streams. Many of the hills have large areas of exposed rock and enormous boulders. This part is heavily timbered with a mix of hardwoods and conifers. This mix of trees on the Arrowhead is spectacularly colorful in autumn.