When I ran the Maah Daah Hey Trail, it was 97 miles. The trail was increased to 144 miles with the addition of the 47-mile trail section called "The Deuce". This trail section was added around 2015.
Route: Maah Daah Hey Trail (ND)
Chad Brackelsberg posted:
"On 8-9 August 2011, I (Chad Brackelsberg) ran the Maah Daah Hey Trail in North Dakota from north to south. I ran the trail supported in a time of 25:56:00. The trail conditions were rough due to the very wet spring and summer in ND. There were numerous landslides (probably a total of 2 miles), very tall and overgrown grass, and lots of knee deep mud holes. To my knowledge, the only other full running of the Maah Daah Hey Trail was by David Hollands in 2003 in a time of 32:53. I have posted a full run report at brackblogs.sharepnt.com/archive/2011/08/11/now-i-know-why-it-is-called-the-badlands.aspx."
Brackelsberg's blog link is broken. This article says his route was 97 miles. Below, Brackelsberg indicates that the trail was increased to 144 miles in 2015, and according to the Maah Daah Hey Trail Association the MDHT is 144 miles, so the FKT route is the full 144 miles.