Grassi Bog Conservation Area

Take in the sounds of frogs and singing songbirds on the trails that loop around Grassi Bog in Marion. This former cranberry bog, which has been restored to a more natural marsh, provides a great place for an easy walk, trail run, or wetland exploration with kids.


Metal bridge across a stream at Grassi Bog in Marion.

Grassi Bog has sturdy metal bridges across its former spillways, where you can watch the water flow by and look for wildlife.

Peaceful wetlands are hidden in plain sight at Grassi Bog, located just off Marion’s busy Route 6. Once a cultivated cranberry bog, this quiet spot is now a place where people can take a walk and spot wildlife. Explorers of all ages will enjoy the bog’s flat loop path, which is an excellent spot for a trail run or to walk your dog.


Grassi Bog’s path loops for roughly three-quarters of a mile around the cranberry bog and across its former fields and spillways. The trail is set on an old service road, making it flat, wide, and easy to navigate. You can walk the large loop around the bog’s edges, or make your way through the open grid of paths that crisscross through the bog cells. (Download trail map)

Habitats & Wildlife

Like nearby Goldavitz Bog and Aucoot Woods’ White Eagle Parcel, Grassi Bog offers a window into how wetlands can be restored after human disruption. With support from the National Resources Conservation Service, the town of Marion improved the flow of water through the bog and replaced invasive species like phragmites with native plants. Grassi Bog is now a sanctuary for frogs, turtles, fish, and birds.

As you walk, watch for fierce little Cooper’s hawks hunting from the skies above the bog trails and wintering sea ducks resting in the water. The town created new habitat here for spotted turtles, an uncommon species in Massachusetts due to wetland loss. A quiet observer may be able to spot these shy, easily startled turtles basking at the edge of shallow waterways.

Property Owned By
Size: 36.55 acres
Hours: Dawn to dusk
Parking: Medium-sized unpaved parking area
Trail Difficulty: Easy
Dogs: Yes (under voice control)
Facilities: None
Boat Ramp: No
ADA Accessible: No

Please follow all posted rules and regulations at this property.

Address & Contact Information
813 Mill St.
Marion, MA 02738
41.688020, -70.774209
Town of Marion: (508) 748-3520

Please follow all posted rules and regulations at this property.

Grassi Bog Conservation Area
Marion, MA
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