The Marathon Loop will be a 26.11-mile continuous off street, multiuse paved trail around Billings. The dotted lines indicate connections yet to be made.

City County Planning has conducted feasibility studies on each section:

Highway 3 (the Skyline Trail) was found to be feasible and a highly desirable trail to connect Swords Rimrock Park to Zimmerman Park. The Highway 3 Corridor Study was completed in 2015. Billings TrailNet is currently working to make this connection by collaborating with the City of Billings, Montana Department of Transportation and the City Billings Parks and Recreation Departments. BTN is raising the money to build the trail.

Access from the Billings rims to the valley below is more complex. Engineers must overcome issues such as the unstable sandstone, steep grades and narrow roads. Creating a trail is possible however, with enough funding to create a safe multiuse trail. The Rims to Valley Study was completed in 2016.

A connection between the end of the multiuse trail on Shiloh Road at the Zoo toward Riverfront Park to the east will make the southern most connection. The Zoo Montana to Riverfront Park Feasibility Study was completed in 2014.

Finally, making the connection between Riverfront Park and Mystic Park to the north, along the Yellowstone River was formally studied and the Yellowstone Riverfront Trail Feasibility Study was published in 2012. Currently, the best way to ride, walk or run between Riverfront Park and Mystic Park via the Marathon Loop is to exit Riverfront Park from Washington Street on the northeast side of the park, head east on Riverside Drive to Garden Avenue and turn east on Belknap to connect to the Jim Dutcher Trail.