| Suncook River | |
| Pushpin Map: | New Hampshire#USA |
| Pushpin Map Size: | 250 px |
| Subdivision Type1: | Country |
| Subdivision Name1: | United States |
| Subdivision Type2: | State |
| Subdivision Name2: | New Hampshire |
| Subdivision Type3: | Counties |
| Subdivision Name3: | Belknap, Merrimack |
| Subdivision Type4: | Towns |
| Subdivision Name4: | Gilmanton, Barnstead, Pittsfield, Chichester, Epsom, Pembroke, Allenstown |
| Length: | 35.7miles |
| Source1: | Crystal Lake |
| Source1 Location: | Gilmanton Ironworks |
| Source1 Coordinates: | 43.4358°N -71.3036°W |
| Source1 Elevation: | 623feet |
| Mouth: | Merrimack River |
| Mouth Location: | Suncook |
| Mouth Coordinates: | 43.1275°N -71.4639°W |
| Mouth Elevation: | 195feet |
| Tributaries Left: | Webster Stream, Big River, Crooked Run, Little Suncook River, Bear Brook, Boat Meadow Brook |
| Tributaries Right: | Kelley Brook, Perry Brook |
The Suncook River is a 35.7adj=midNaNadj=mid[1] river located in central New Hampshire in the United States. It is a tributary of the Merrimack River, which flows to the Gulf of Maine.
The Suncook River begins at the outlet of Crystal Lake in the town of Gilmanton, New Hampshire. The village of Gilmanton Ironworks is located at the lake's outlet. The Suncook flows south two miles to the Suncook Lakes (Upper and Lower) in Barnstead. Below the lakes, the river passes through the village of Center Barnstead and enters the town of Pittsfield, whose village is centered on a 19th century dam on the river.
The river continues south through the towns of Chichester and Epsom, and then forms the town boundary between Pembroke and Allenstown. Shortly before reaching the Merrimack River, the Suncook drops in, a natural waterpower site that led to the growth of the village of Suncook.
On May 16, 2006, the Suncook River, responding to the highest rainfall amounts in at least 70 years (more than dropped by a low-pressure system in three days on Concord, New Hampshire), rose to flood level and backed up behind an old mill dam, which produced a shallowly-sloping pool that overtopped a sand and gravel quarry, connected with a downstream section of channel, and cut a new shorter channel at 25–50 meters per hour in the town of Epsom.[2] Two previous channels, around Bear Island, were left dry. The new river course, approximately a mile long, is the largest channel change in a river in New Hampshire since systematic topographic mapping began in the state in the early 20th century.[3]
On September 3, 2018, there was news that work had begun to stabilize the Suncook River in its new course.[4]
In 1934, the American composer Alan Hovhaness (1911–2000), who spent time with his maternal family members in Pittsfield, New Hampshire, during his youth, wrote a fantasy for cello and piano entitled Legend of the Sunkook Valley (Op. 1, no. 4).