This cache is hidden in the Welch Pond Conservation Area in Bolton. It is hidden off the trail in an area surrounded by a stonewall.
You will have to leave the trail and go through the opening in the stonewall. See the waypoint/coordinates for the opening in the stonewall.
NOTE: On the inside of the lid are letters with corresponding numbers that are part of the coordinates for the MYSTERY CACHE. Be sure to write them down or take a pic of them as you will need them to figure out the coordinates once you have found all three traditional caches on the trail.
Here is a link to a map of and information on the Welch Pond Conservation Area:
Welch Pond / Gould Memorial Trail
Congratulations to BILL THE CAT 89 for being FIRST TO FIND!