The Connecticut River is a major river in the New England region of the United States. The region's longest, it flows roughly southward for through four states. Rising 300 yards (270 m) south of the U.S. border with Quebec, Canada, it discharges into Long Island Sound between Old Saybrook and Old Lyme, Connecticut. Its watershed encompasses , covering parts of five U.S. states and one Canadian province, composed of 148 tributaries, 38 of which are major rivers. It produces 70% of Long Island Sound's fresh water, discharging at per second.

The Connecticut River Valley is home to some of the northeastern United States' most productive farmland, as well as the Hartford–Springfield Knowledge Corridor, a metropolitan region of approximately two million people surrounding Springfield, Massachusetts, and Hartford, Connecticut.

History The word "Connecticut" is a corruption of the Mohegan word quinetucket and Nipmuc word kwinitekw, which mean "beside the long, tidal river". The word came into English usage during the early 1600s to name the river, which was also called simply "The Great River". It was also known by New Netherlanders as Versche Rivier, or the fresh river.

Early spellings of the name by European explorers included "Cannitticutt" in French or in English.

Pre-1614: Native American populations Archaeological digs reveal human habitation of the Connecticut River Valley for 6,000 years before present. Numerous tribes lived throughout the fertile Connecticut River valley prior to Dutch exploration beginning in 1614. Information concerning how these tribes lived and interacted stems mostly from English accounts written during the 1630s.

The Pequots dominated a territory in the southern region of the Connecticut River valley, stretching roughly from the river's mouth at Old Saybrook, Connecticut, north to just below the Big Bend at Middletown, Connecticut. They warred with and attempted to subjugate neighboring agricultural tribes such as the Western Niantics, while maintaining an uneasy stand-off with their rivals the Mohegans.

The Mattabesset (Tunxis) tribe takes its name from the place where its sachems ruled at the Connecticut River's Big Bend at Middletown, in a village sandwiched between the territories of the aggressive Pequots to the south and the more peaceable Mohegans to the north.

The Mohegans dominated the region due north, where Hartford and its suburbs sit, particularly after allying themselves with the Colonists against the Pequots during the Pequot War of 1637. Their culture was similar to the Pequots, as they had split off from them and become their rivals some time prior to European exploration of the area.

The agricultural Pocomtuc tribe lived in unfortified villages alongside the Connecticut River north of the Enfield Falls on the fertile stretch of hills and meadows surrounding Springfield, Massachusetts. The Pocomtuc village of AgawamMeaning "landing place" or "place for unloading canoes." eventually became Springfield, situated on the Bay Path where the Connecticut River meets the western Westfield River and eastern Chicopee River. The Pocomtuc villagers at Agawam helped Puritan explorers settle this site and remained friendly with them for decades, unlike tribes farther north and south along the Connecticut River. The region stretching from Springfield north to the New Hampshire and Vermont state borders fostered many agricultural Pocomtuc and Nipmuc settlements, with its soil enhanced by sedimentary deposits. Occasionally, these villages endured invasions from more aggressive confederated tribes living in New York, such as the Mohawk, Mahican, and Iroquois.

The Pennacook tribe mediated many early disagreements between colonists and other Indian tribes, with a territory stretching roughly from the Massachusetts border with Vermont and New Hampshire, northward to the rise of the White Mountains in New Hampshire. The Western Abenaki (Sokoki) tribe lived in the Green Mountains region of Vermont but wintered as far south as the Northfield, Massachusetts, area. The (Sokoki) tribe migrated to Odanak, Quebec following the epidemics and the wars with the settlers but returned to Vermont.

1614–1636: Dutch and Puritan settlement In 1614, Dutch explorer Adriaen Block became the first European to chart the Connecticut River, sailing as far north as Enfield Rapids. He called it the "Fresh River" and claimed it for the Netherlands as the northeastern border of the New Netherland Colony. In 1623, Dutch traders constructed a fortified trading post at the site of Hartford, Connecticut, called the Fort Huys de Hoop ("Fort House of Hope").

Four separate Puritan-led groups also settled the fertile Connecticut River Valley, and they founded the two large cities that continue to dominate the Valley: Hartford (est. 1635) and Springfield (est. 1636). The first group of pioneers left the Plymouth Colony in 1632 and ultimately founded the village of Matianuck (which became Windsor, Connecticut) several miles north of the Dutch fort. A group left the Massachusetts Bay Colony from Watertown, seeking a site where they could practice their religion more freely. With this in mind, they founded Wethersfield, Connecticut, in 1633, several miles south of the Dutch fort at Hartford.

In 1635, Reverend Thomas Hooker led settlers from Cambridge, Massachusetts, where he had feuded with Reverend John Cotton, to the site in Connecticut of the Dutch Fort House of Hope, where he founded Newtowne. Shortly after Hooker's arrival, Newtowne annexed Matianuck based on laws articulated in Connecticut's settlement charter, the Warwick Patent of 1631. The patent, however, had been physically lost, and the annexation was almost certainly illegal.

The fourth English settlement along the Connecticut River came out of a 1635 scouting party commissioned by William Pynchon to found a city on the river's most advantageous site for commerce and agriculture. Pynchon's Massachusetts scouts located the Pocomtuc village of Agawam, where the Bay Path trade route crossed the Connecticut River at two of its major tributaries—the Chicopee River to the east and the Westfield River to the west—and just north of Enfield Falls, the river's first unnavigable waterfall. Pynchon surmised that traders using any of these routes would have to dock and change vessels at his site, thereby granting the settlement a commercial advantage. It was initially named Agawam Plantation and was allied with the settlements to the south that became the state of Connecticut. In 1641, Springfield splintered off from the Hartford-based Connecticut Colony, allying itself with the Massachusetts Bay Colony. For decades, Springfield remained the Massachusetts Bay Colony's westernmost settlement, on the northern border of the Connecticut Colony.

Of these settlements, Hartford and Springfield quickly emerged as powers. By 1654, however, the success of these English settlements rendered the Dutch position untenable on the Connecticut River. A treaty moved the boundary westward between the Connecticut Colony and the New Netherland Colony to a point near Greenwich. The treaty allowed the Dutch to maintain their trading post at Fort Huys de Hoop, which they did until the 1664 British takeover of New Netherland.

Border disputes The Connecticut River Valley's central location, fertile soil, and abundant natural resources made it the target of centuries of border disputes, beginning with Springfield's defection from the Connecticut Colony in 1641, which brought the Massachusetts Bay Colony to the river. In 1640, the Massachusetts Bay Colony asserted jurisdiction over lands surrounding the river; however, Springfield remained politically independent until tensions with the Connecticut Colony were exacerbated by a final confrontation later that year.

Hartford kept a fort at the mouth of the Connecticut River at Old Saybrook for protection against the Pequot, Wampanoag, Mohegans, and the New Netherland Colony. After Springfield broke ties with the Colony, the remaining Connecticut settlements demanded that Springfield's ships pay tolls when passing the mouth of the river. The ships refused to pay this tax without representation at Connecticut's fort, but Hartford refused to grant it. In response, the Massachusetts Bay Colony solidified its friendship with Springfield by levying a toll on Connecticut Colony ships entering Boston Harbor. Connecticut was largely dependent on sea trade with Boston and therefore permanently dropped its tax on Springfield, but Springfield allied with Boston nonetheless, drawing the first state border across the Connecticut River.

The Fort at Number 4 in Charlestown, New Hampshire, was the northernmost British colonial presence on the Connecticut River until the end of the French and Indian War in 1763. The Abenaki had resisted British colonial settlement for decades, but colonists began settling north of Brattleboro, Vermont, following the war. Settlement of the Upper Connecticut River Valley increased quickly, with population assessments of 36,000 by 1790.

Vermont was claimed by both New Hampshire and New York, and was settled primarily through the issuance of land grants by New Hampshire Governor Benning Wentworth beginning in the 1740s.Wardner, p. 13. New York protested these grants, and the Board of Trade decided in 1764 that the border between the provinces should be the western bank of the Connecticut River.Wardner, p. 41 Ethan Allen, the Green Mountain Boys, and other residents of the disputed area resisted attempts by New York to exercise authority there, which resulted in the establishment of the independent Vermont Republic in 1777Wardner, p. 443 and its eventual accession to the United States in 1791 as the fourteenth state.Van de Water, Frederic. The Reluctant Republic, New York: John Day, 1941. p. 337 Boundary disputes between Vermont and New Hampshire lasted for nearly 150 years. They were finally settled in 1933, when the U.S. Supreme Court reaffirmed King George's boundary as the ordinary low-water mark on the Vermont shore. In some places, the state line was inundated by the impoundments of dams built after this time.

The Treaty of Paris and the 19th century

The Treaty of Paris (1783) that ended the American Revolutionary War created a new international border between New Hampshire and the Province of Canada at the "northwesternmost headwaters of the Connecticut". Several streams fit this description, leading to a boundary dispute that resulted in the short-lived Indian Stream Republic, which existed from 1832 to 1835.

The broad, fertile Connecticut River Valley attracted agricultural settlers and colonial traders to Hartford, Springfield, and the surrounding region. The high volume and numerous falls of the river capable of powering mills and waterwheels led to the rise of industry along its banks during the Industrial Revolution. The cities of Springfield and Hartford, in particular, became centers of innovation and "intense and concentrated prosperity."

The Enfield Falls Canal was opened in 1829 to circumvent shallows around Enfield Falls, and the locks built for this canal gave their name to the town of Windsor Locks, Connecticut. The Connecticut River Valley functioned as America's hub of technical innovation into the 20th century, particularly the cities of Springfield and Hartford, and thus attracted numerous railroad lines. The proliferation of the railroads in Springfield and Hartford greatly decreased the economic importance of the Connecticut River. Except for log drives that persisted into the early decades of the 20th century, the river has functioned largely as a center of wildlife and recreation since the late 1800s.

Log drives and the early 20th century