Explore Iowa: Wabash Trace Nature Trail. Southwest Iowa Nature Trails, Inc. (SWINT) established this 63-mile trail through the Loess Hills, in partnership with INHF. It took 10 years to convert this abandoned railroad corridor for use as a trail, but it was worth it. The trail has been frequently recognized as one of the nation’s best. The Wabash Trace Nature Trail travels from Iowa’s beautiful Loess Hills to its southwestern prairies.