Agassiz Rock

Ascend a small hill to where a massive granite monolith left by the last glacier juts into the sky, then pass a swamp where another huge boulder has sat as silent witness for millennia. Big and Little Agassiz Rocks are dramatic examples of giant boulders plucked from bedrock and carried far away by the last glacier. A short loop trail leads up Beaverdam Hill where Little Agassiz Rock appears as a giant granite monolith silhouetted against the sky. It rests – seemingly precariously – on a small jagged stone, leaving an opening below. A short distance away, other boulders lie perched on the edge of this glaciated upland. Below, in a small shrub swamp, rests thirty-foot-tall Big Agassiz Rock. No one knows how far below the ground it is buried. As the glaciers scoured this landscape, the mass of bedrock forming the hill proved more resistant than the surrounding soil, forcing the bottom of the glacier up and over the hill. The north side was smoothed and the south side left steep and rugged as the glacier broke off chunks of rock as it passed. In October 1874, a group of students from the Essex Institute formally named the site to honor Louis Agassiz (1807-1873), the professor of natural history at Harvard University who first theorized that the rocks that dot New England’s landscape were shaped and deposited by glaciers. Agassiz supposedly visited the site at the suggestion of its then-owner, Frederick Burnham. Agassiz found its erratics great lessons to advance his theory and to bring it to the attention of science. Prior to Agassiz’s theory, it was widely believed that the scattering of rocks throughout New England was the result of Noah’s great flood.


398 Souther Ave #334 Manchester-by-the-Sea, MA 1944

Driving Directions

From Rt. 128 (exit 15), take School St. north for 0.5 mi. Entrance and roadside parking (10 cars) on right.

Notes & Advisories

Trails: 1-mile loop trail (moderate hiking) takes in both Big and Little Agassiz Rocks. Following long periods of rain, when the water table is high, the immediate area surrounding Big Agassiz Rock can be flooded.


  • Natural Resources
  • Parks
  • Wildlife Viewing


  • Appropriate for all ages
  • Parking Available