Corridor Monitoring Program


The Maine Appalachian Trail Club is extremely fortunate to have much of the AT in Maine surrounded by 34,000 acres of National Park Service land, but caring for and protecting that land is essential.
MATC Corridor Monitors walk the Trail and the corridor boundary lines looking for timber trespass, trash dumping, illegal motor vehicle crossings, and other encroachments that threaten the condition of corridor resources and reduce the quality of the AT experience. The surveyed boundary itself must be kept clearly visible so that neighboring landowners know where it is, and the regular inspection of boundary line monuments helps to protect against a need for very expensive re-surveys that could be required if monuments are lost. Corridor monitoring offers an opportunity to get off the AT footpath and explore some incredibly beautiful areas that those who only walk the Trail never see. For those seeking something new in Trail stewardship, as well as a little excitement and a chance to satisfy an urge to explore, corridor monitoring may be just what you are looking for. At present, the sections listed below are available for monitoring.

The Thrill of Discovery: Musings of a Corridor Monitor –  An essay by Bill Geller, a corridor monitor for the MATC. “That monument marker was right here when I found it last year, I don’t see it?”  Five minutes later I did find it without having to get out my hand saw, clippers, loppers, line ropes, tape measure and assorted digging instruments. An essay by Bill Geller, a corridor monitor for  the MATC…” Read “The Thrill of Discovery”



(Updated 1/7/2020)

 There are still some great opportunities for becoming involved in this exciting aspect of caring for the Appalachian Trail in Maine.  For information about corridor monitoring and field training sessions, visit the MATC website at or contact me (Dave Field) at 862-3674,  You must participate in a field training session before an assignment will be made permanent.  If you are unable to join a group session, I will make arrangements to train you on your own section. Note: The mileages given for each section are the distances along the boundary lines on each side of the corridor that a corridor monitor would need to walk to cover that section. For assignments on State-owned land, there are no surveyed boundary lines and monitoring is generally done by walking along the A.T. and observing the surroundings.

Section 14.  B Pond Road to East Branch of the Pleasant River.  This 7.6-mile section begins near Crawford Pond, passes over Little Boardman Mt., and skirts Mt. View Pond.  The terrain varies from gentle to challenging with plenty of good views.  The boundary was surveyed in 1995.  Access is very good over the Jo-Mary road system from Route 11.

Section 18. White Brook Trail to Gulf Hagas Mountain.  This four-mile section was surveyed in 1994, but the lines are still in fairly good shape.  You can drive to within a 20-minute walk of the north side, east end of the section. The boundary was surveyed in 1994.

Section 20. The Gulf Hagas Preserve. This very accessible section with 3.8 miles of boundary line is once more available for assignment.

Section 36b. East of the North Peaks Trail to West of the Moxie Bald Bypass Trail. This section, with 5.3 miles of corridor boundary lines, is accessible via a hike along the A.T. from the “A.T. Road” on the west side or from Bald Mt. Pond on the east. The easterly line is in poor condition but the western line was renewed a few years ago. This is a challenging assignment.

Section 43. North Branch of Carrying Place Stream to Sandy Stream. This 6.8-mile section covers mostly flat terrain in the Carry Ponds area. Access is good over logging roads from the Long Falls Dam Road or from the east. The lines are old (1992) but some have been renewed by the previous monitor.

Section 48/49. Little Bigelow to the West Peak of Bigelow. All of this section is in the Bigelow Preserve and has no exterior corridor boundary lines. Beautiful scenery.

Section 61. Little Swift River Pond to Sabbath Day Pond Lean-to. This section has just become open. It is entirely on State-owned land, so there are no exterior corridor boundary lines. Monitoring is done by walking along the A.T. and looking for problems.

Section 62. Sabbath Day Pond to Highway 17. From Sabbath Day Pond to Moxie Pond this section is on State-owned land so has no corridor boundaries. The rest of the section involves 2.8 miles of surveyed line on very gentle terrain. Access is excellent from Route 17 and an old logging road that leads to the northerly end of the section.

Section 64. Bemis Stream Trail to Former Clearwater Brook Trail. This assignment involves 4.2 miles of surveyed boundary lines over rugged Elephant Mountain and along the sides of Bemis Mountain. It is very accessible from the southerly end if you can drive over a slightly rough gravel road and from the northerly end via a hike over the Bemis Stream Trail.

Section 65. Former Clearwater Brook Trail to South Arm Road.  This section begins at the bottom of the saddle between Old Blue and Elephant mountains, runs up over old blue and down into Black Brook Notch. Excellent access at the South Arm Road and an easy walk into the other end if you have a vehicle that can go over a slightly rough gravel road. The assignment includes 6.5 miles of surveyed  boundary lines.


What is a tract and what is the A.T. corridor? 

A tract is a unit of land that includes the Appalachian Trail within its boundary. One tract is connected to the next tract, and the next, and so on. The connected tracts define the A.T. corridor through Maine, from Katahdin to the Mahoosucs. The A.T. runs north-south inside the corridor boundary. Don’t assume the corridor is always 1,000 feet wide. Tracts vary in size and width. NPS, BSP, BPL and others own the A.T. corridor in Maine. The Maine Appalachian Trail Club looks after the corridor lands and the trail.

Are corridor monitoring sections and trail maintenance sections the same?

When the A.T. corridor was laid out across Maine, the tract and corridor sections did not coincide with trail maintenance sections. Some MATC designated corridor monitoring sections nearly coincide with trail maintenance sections, others don’t. This is why there are 70 corridor monitoring sections and 90 trail maintenance sections on the A.T. in Maine.

Is maintaining a section of trail the same as monitoring a section of corridor

The two are very different jobs. Maintaining the A.T. is about assessing, planning and responding to conditions right on and immediately along the trail. The scope of trail maintenance is trail focused, period.

Monitoring is tract and corridor focused. Corridor monitors assess and respond to conditions beyond the immediate trail, all the way out to the boundary line of the corridor tract. It includes assessing activities that may be occurring just outside the corridor, or activities that may be intruding across the boundary line into the interior of the corridor.

Some examples are timber trespass, off-road vehicles, dumping, and other alterations of the tract from human activity. Changes in the natural environment from insects, disease, or forest fires can also be a part of the scope of corridor monitoring.

Can I be a corridor monitor, but not maintain a section of trail?

Certainly. While some trail maintainers also monitor the immediate corridor, others don’t. If corridor monitoring appeals to your interests, there are plenty of corridor monitoring sections along the A.T. in Maine that are available for your care and contribution.

Corridor Monitoring activity means contracting to:

  • Get off the trail with map and compass and go out across the tract.
  • Walk on out to the boundary lines of the corridor section.
  • Look for signs of intrusion into the corridor tract.
  • Walk the boundary lines more often when activity is occurring next door.
  • Report incidents and your annual activity in a timely fashion.
  • Revisit and check up when adjacent activities or corridor incidents occur.
  • Communicate with your A.T. District Overseer and Overseer of Lands

Who do I contact to become an MATC Corridor Monitor?

David Field
MATC Overseer of Lands
191 Emerson Mill Road
Hampden, Maine 04444
For more on corridor monitoring, Dave says to read this “great article on the work that ATC surveyor Sally Naser has been doing in northern New England with her tiny boundary maintenance crew.” The 929kb pdf file is from the latest issue of AT Journeys. It can be downloaded from the MATC site by using this url: Boundary Monitors Mahoosucs – ATJ JanFeb2008.

To view or print a PDF (Portable Document Format) file, you need the Adobe Reader, version 5 or later, on your computer. If you don’t already have it, you can download a free copy of the Reader from the Adobe Web site at Adobe Acrobat. Installation instructions are available from the Adobe website.

Corridor Monitoring Annual Reports