Mt Greylock, Thunderbolt Trail (MA)

Berkshire County, Massachusetts, United States

13.0 miles (21.0 km) · 3,576 ft elevation gain · Loop · trail · Route

Mt Greylock, Thunderbolt Trail (MA) covers 13.0 miles across Berkshire County, Massachusetts, United States. Runners face 3,576 feet of climbing with 3,576 feet of loss. The largest climb extends 2.1 miles, gaining 2,296 feet. The course averages 275 feet of vertical gain per mile. The course is 58% runnable, with the remainder requiring hiking on steep or technical sections. Trail comprises the majority of the course. Terrain difficulty is rated as mountainous. Difficulty is rated 15.2 out of 10, placing it in the 79.1th percentile. Popular among trail runners and hikers seeking Massachusetts adventures.