FATMAP difficulty grade
Traversing the length of Isle Royale NP, the Greenstone Ridge Trail offers trail runners nearly 40 miles of epic and remote singletrack lined with stunning views, wildlife, and wetlands.
One [local source](https://www.michigantrailmaps.com/member-detail/isle-royale-np-greenstone-ridge-trail-map-1/) describes it as a "beautiful and personally fulfilling hike," that every backpacker should experience at least once, while the mere epic-ness of running the distance draws ambitious trail runners to stake their claim at a single-day attempt. According to the official [FKT website](https://fastestknowntime.com/route/greenstone-ridge-trail-mi), the fastest documented times as of 2020 crests the 8-hour mark, contrasting with hikers who often plan 3 to 5 days to hike the trail.
Rumors of even faster times have circulated on various blogs and publications, but most are simply hearsay among the trail running community. Though there is no preferred direction to run the trail, the most challenging aspect of planning the Greenstone Ridge Trail is the logistics.
While the western terminus is in Windigo, the official eastern terminus is the Hidden Lake Dock across the harbor from Rock Harbor Visitor Center.
A boat ride or paddle is necessary to reach Rock Harbor and can be rented from the [Rock Harbor Lodge](https://www.rockharborlodge.com/) if needed. To avoid crossing the water by boat, a popular alternative is to connect the Mount Franklin Trail to either Rock Harbor or Tobin Harbor Trail.
Both lead to Rock Harbor Visitor Center, though it's unclear if the route addendum would qualify a runner for the FKT leaderboard. The best time of year to plan your run is in the spring or fall, avoiding the peak heat of the summer.
Though the average daytime temperatures may seem mild, the wetlands are host to an almost-unbearable selection of insects.
As long as it is sufficiently treated or filtered first, water is also abundant along the trail, though you may have to leave the trail to find it along the remote ridgetop exposures. Even if a full run or hike does not make the agenda for your trip, you can still explore portions of the Greenstone Trail on classic day hikes including [Lookout Louise](https://fatmap.com/routeid/2707772/lookout-louise/), [Mount Franklin](https://fatmap.com/routeid/2707774/mount-franklin/), and [Mount Ojibway](https://fatmap.com/routeid/2709477/), all somewhat closer to Rock Harbor than Windigo.
Sources: https://www.michigantrailmaps.com/member-detail/isle-royale-np-greenstone-ridge-trail-map-1/ https://fastestknowntime.proboards.com/thread/263/greenstone-ridge-trail-isle-royale