Stone's Bridge,
photographed from the modern bridge. The earliest bridge in this area was built probably in 1647; it began to be called the "Old Bridge" after a "New Bridge" was built in 1674 at the site of the present stone bridge. The "New Bridge" was destroyed in 1771 and rebuilt the following year, and in winter 1775-6 it was this version of the bridge over which Colonel Henry Knox led 60 tons of cannon and supplies from Fort Ticonderoga, New York, to aid General Washington in the Siege of Boston. Starting around 1820, the "New Bridge" began to be called "Stone's Bridge," since this region was known as Stone's End. The present stone structure dates from 1857, as shown by Thoreau's entry for July 31, 1859, in the twelfth volume of his Journal.

"Like some ancient Roman aqueduct set down in the New World, the remains of an old stone bridge stood stark and lonely in its river setting. With its weathered blocks of stone, its four remaining arches, its western end fallen away, it seemed surrounded by a venerable air, enveloped in an atmosphere of great antiquity." A Conscious Stillness: Two Naturalists on Thoreau's Rivers by Ann Zwinger and Edwin Way Teale (1982).

Another resource: Matthew Eisenson's Sudbury River Canoe Trail report, pp. 5–6.

The canoe trail starts at the Ox-Bow, goes past Stone's Bridge, and continues downstream for about 15 miles, passing through the Great Meadows National Wildlife Refuge, and ending in Concord, where the Sudbury River joins the Assabet River to form the Concord River. This route was followed by Henry David Thoreau, though in his time the Sudbury River was often considered simply the upper part of the Concord River. In addition to his journal, see A Week on the Concord and Merrimack Rivers. (Thoreau's maternal grandmother, Mary (Jones) Dunbar, was descended from Nathaniel Treadway, Jr., son of Nathaniel and Mary (Howe) Treadway and nephew of Edward Howe, d. by mid-1644, whose will names John Stone and Nathaniel Treadway [Jr.] as executors and residuary legatees. John Stone and Nathaniel Treadway [Jr.] had been next-door neighbors in Sudbury; Nathaniel was Edward's nephew, and John's wife was probably Edward's wife's niece. In 1666 John and Nathaniel acquired 300 acres in Saxonville from Thomas Mayhew in satisfaction of a debt Mayhew owed Howe.)