The northern terminus is just south of Mt. Monadnock at the NH/MA state border, and the southern terminus is at the Long Island Sound in Guilford, CT. It is just over 200 miles long, and it is one of the National Scenic Trails. It runs along rugged traprock ridges.

Lee-Stuart Evans ran the entire NET & described it briefly as follows:

There are numerous possibilities, and no one FKT route has yet become standard.  Here is some of the discussion that happened on our old website:

Tim Seaver (7/11/2014):

Mount Mansfield, Sunset Ridge/Maple Ridge Loop w/summit (VT)

I've been running this loop for almost 20 years, and still think it's one of the finest in New England.

Joe's Guide to Acadia National Park describes the route:

Phil Maynard proposed a traverse of Acadia National Park:

[Note this is similar to, but shorter than, the Acadia Mountain Marathon route.]

Dan Rosenthal proposed the route:

I loved the idea of an Acadia Traverse but didn't have the time or transportation to complete it and make time for the family.  So, my Blackwoods loop originated from a problem.  How can I have the most epic run in Acadia on a limited time frame with a start and finish at Blackwoods campground?  I was intrigued that two trails exited the campground.  My route was influenced by Phil Maynard's route. 

Posted by Adam Wilcox:

From the New Hampshire State Parks blog:

In the summer of 2001, Elijah Barrett of New Ipswich, NH set the official record ascent time up Mt. Monadnock taking just 24 minutes and 44 seconds to reach the summit via the White Dot Trail. The time was officially timed by Monadnock Patrol Staff; a service they do not really offer much. Elijah beat out former Monadnock Mountain Patrolman Ken Peterson’s previous record ascent time of 25 minutes and 45 seconds set a few years prior.

Robert Rives posted the Swan Song route:

Hi all White Mountain running/speed hiking enthusiasts! I have a tasty new loop for us to chew on...

ardentambulations.blogspot.com/2014/07/the-swan-song-loop.html

Sam Price posted about the route & history:

"Without doing any research, I ascertained that there was no Fastest Known Time. History was within our grasp." --- TEO, FKT, Legendary Cube-Smarts Traverse, 11/18/12, www.vftt.org.

There are some great accounts of folks trying for a single traverse of this section of the AT and variations: