New Jersey, US
This 20 mile route travels along the Appalachian Trail from the Dunnfield Creek parking lot to just past Crater Lake, where it descends down the Kittatiny ridge to Buttermilk Falls (or reverse). The route passes many New Jersey landmarks including Sunfish Pond and Catfish Fire Tower.
I will be making an unsupported FKT attempt of this route 'Out N' Back' on 5/18. I'll be tracking the attempt using a Coros Vertix watch and will publish on Strava as well.