Upper Sioux Agency State Park is a 1,280-acre area of prairie land, bluffs and wooded hills. Hiking, horseback riding, snowmobiling and cross-country skiing are all popular here. Camping is also a common occurrence.
The park offers 18 miles of easy to moderate hiking that takes you along the Yellow Medicine River Valley. The views are great.
From the town of Granite Falls at the intersection of State Hwy 212 and 23, go south on St. Hwy 23, about one block to State Hwy 67. Turn left on 67 and go eight miles to park entrances. The first of the park's three entrances will take you to the horse rider campground. The second entrance takes you to the main park entrance. The last entrance takes you to the campground.
http://www.tripleblaze.com/trail.php?c=3&i=4554