The (orange blazed) Pinchot Trail is a ~22 mile trail in the Lackawanna State Forest, near Lehigh, PA.

The route has been updated recently and the gpx here reflects that.

Most notable is a section to the south and a section on the west side of the loop.

Official Route

PA DCNR - Pinchot Trail

Information on the 60-mile Loyalsock Trail is at http://www.pahikes.com/trails/loyalsock-trail. The trail is maintained by the Alpine Club of Williamsport.

The Long Island Greenbelt Trail runs about 32 miles from Heckscher State Park to Sunken Meadow State Park. Evolution of the FKT is documented on the old site. Barney Fortunato ran this 32-mile route a couple of times with a best time of 4h41m15s on July 25, 2015.  Others have run it, but we know of no faster completion.
Here's a link to the Long Island Green Belt Trail Conference (maps & information).

Wikipedia says:

The Finger Lakes Trail consists of a network of trails in New York. The trail system is administered by the Finger Lakes Trail Conference (FLTC), a non-profit organization, composed primarily of volunteers.

Previous eastern terminus of the trail in the Catskill Park, where it meets the Long Path.

Staff note: This route has seen a lot of bicycle activity, but currently we only accept FKTs for running/hiking this. 

"couloirman" posted:

The Great Allegheny Passage (GAP) is a 150-mile trail from Cumberland, MD, to Pittsburgh, PA. The GAP is mainly well groomed crushed limestone that rides fast - most interest in this trail has been by cyclists.  However, on our old website a hiker claimed to have walked the GAP in 137h55m in June 2016 (self-supported).

Joe Delano posted the route & a time of 2h51m33s (1/18/2015):