It is also credited with being the oldest hydroelectric dam in the country.Other significant historic sites along the Upper Merrimack include the Gold Star Sod Farm residence and barn in Canterbury, and the Timothy Walker House and the Sullivan Farm in Concord.
This population of Karner blue butterflies, listed as "globally very rare", is the only one in all of New England.
The New Hampshire Natural Heritage Inventory has also identified the following rare species as occurring in the river corridor: Fowler's toad, Blanding's turtle, blue-gray gnatcatcher, blunt-leaved milkweed, wild senna, ram's head lady slipper, golden heather, wild lupine, pink wintergreen, burgrass, and fall witchgrass.
History The Merrimack River played a pivotal role in the early settlement and subsequent development of the region.
The river and its banks provided many resources for early inhabitants, including fish, migratory birds, and an important route for communication and transportation.
Maintenance of this level of water quality is critical to ensuring the river's future use for water supply and recreational purposes.
For these reasons, along with its designation into the NH Rivers Management and Protection Program, the Upper Merrimack was found to be eligible for inclusion in the National Wild and Scenic Rivers System, administered by the National Park Service.It is one of two segments protecting nearly 45 miles of the Merrimack River designated into the NH Rivers Management and Protection Program in June 1990.During the 19th century industrial era, the Merrimack River was the most noted waterpower stream in the world.The river's banks provide nesting sites for the bank swallow and the kingfisher.Its corridor provides significant wintering habitat for the federally-listed threatened bald eagle, and is seasonally important to the state-listed threatened osprey.Wildlife and Plant Resources As one of New England's major north-south running rivers, the Upper Merrimack River serves as an important migratory route for waterfowl and songbirds.