The town of Harrisville is often identified by its National Historic Landmark-designated 19th century water-powered mill complex and village in the center of the town. Less well-known is the history and significance of the town’s west side, including the Chesham Dam.
 
The Chesham Dam was determined eligible for listing in the National Register of Historic Places as part of the state’s proposed dam rehabilitation project. Its significance is not directly related to that of the village of Harrisville.  Instead, it relates to industrial development downriver in Marlborough.
 
The Chesham Dam was completed in 1869 by the Breed Pond Company, which was founded in 1851 to remedy summer low flow conditions on the Minnewawa that limited the productivity of Marlborough enterprises. The Breed Pond Company created Chesham Pond by purchasing properties down river from Breed Pond in what was known as the Great Meadows, beginning in 1868.  The dam was likely completed in 1869 or 1870. When it was originally constructed, the Chesham Dam was a stone and timber crib dam with a long “cap log” running across the top of the dam and 16-inch flash boards. With the construction of the dam, Chesham Pond was created. This was one of several dams and reservoirs maintained by the Breed Pond Company in the area.
 
The dam has undergone several upgrades and changes over its lifetime, including:

• The addition of the dressed stone abutments that supported a railroad bridge.  The bridge was built in 1877 and removed between 1936 and 1950, but the stone abutments with bridge seats remain today.
• Improvements to the crib dam in 1921, as evidenced by a date stone that appears in historic photos. Although 1921 is usually given as the date of construction of the current dam, it seems likely that parts of the earlier dam survive.
• New concrete added to the spillway in 1937, raising the face about 4 feet.
• In 1949 a new concrete cap was installed, the top of the dam was rounded, concrete was added on the downriver side of the spillway, and the 1921 sluiceway was replaced.

 
Although it was still owned by the Breed Pond Company, the dam was operated in conjunction with Ashuelot, which generated power at the Minnewawa hydroelectric plant in Marlborough beginning in the early 1920s.  In 1956 the Cheshire dam and reservoir were transferred from the Breed Pond Company to Public Service of New Hampshire (PSNH), which continued to use the reservoir for water storage associated with its Minnewawa power station well into the 1960s. In 1967 PSNH gave the Chesham dam and pond to the State of New Hampshire, along with Silver Lake, Seaver Reservoir, Howe Reservoir, and Child’s Bog.  Since that time, Chesham Dam has been operated by the state for recreational use.