Question: Amhert, Massachusetts, is a town located in the valley of the longest river in which region of the United States?

full_context: Document 1: Connecticut River: The Connecticut River is the longest river in the New England region of the United States, flowing roughly southward for 406 mi through four U.S. states. It rises at the U.S. border with Quebec, Canada, and discharges at Long Island Sound. Its watershed encompasses five U.S. states and one Canadian province, 11260 sqmi via 148 tributaries, 38 of which are major rivers. It produces 70% of Long Island Sound's fresh water, discharging at 19600 cuft per second.
Document 2: 1980 Amherst, Massachusetts water shortage: The 1980 Amherst, Massachusetts water shortage was a water crisis in Amherst, Massachusetts that amongst other things, closed the University of Massachusetts Amherst for three days. It came at a time when communities across the state were experiencing water crises of their own in the region's worst drought since 1965.
Document 3: Columbia River: The Columbia River is the largest river in the Pacific Northwest region of North America. The river rises in the Rocky Mountains of British Columbia, Canada. It flows northwest and then south into the US state of Washington, then turns west to form most of the border between Washington and the state of Oregon before emptying into the Pacific Ocean. The river is 1243 mi long, and its largest tributary is the Snake River. Its drainage basin is roughly the size of France and extends into seven US states and a Canadian province. The fourth-largest river in the United States by volume, the Columbia has the greatest flow of any North American river entering the Pacific.
Document 4: University of Massachusetts Amherst: The University of Massachusetts Amherst (abbreviated UMass Amherst and colloquially referred to as UMass or Massachusetts) is a public research and land-grant university in Amherst, Massachusetts, United States, and the flagship campus of the University of Massachusetts system. With approximately 1,300 faculty members and more than 29,000 students, UMass Amherst is the largest public university in New England and is ranked as tied for the 27th best public university in the nation.
Document 5: Saint John River (Bay of Fundy): The Saint John River (French: "Fleuve Saint-Jean" ; Maliseet: "Wolastoq"( )) is a river, approximately 418 mi long, located principally in the Canadian province of New Brunswick, but also in and arising from the province of Quebec and the U.S. state of Maine. It forms part of the Canada–United States border in two different places along its length. The river drains an area of approximately 55000 km2 , of which slightly more than half is located in New Brunswick. Along that portion of the Atlantic shoreline of North America that lies between the St. Lawrence River and the Mississippi River, the Saint John River is the second longest waterway; only the Susquehanna is longer. It has been nicknamed the "Rhine of North America" for its scenery. The river is regulated by hydro power dams located at Mactaquac, Beechwood, and Grand Falls, New Brunswick.
Document 6: Amherst station (Massachusetts): Amherst is a closed intercity rail station in Amherst, Massachusetts formerly served by the Amtrak "Vermonter". It is located at 13 Railroad Street off Main Street, and served the downtown area along with Amherst College and the University of Massachusetts Amherst. The station was closed on December 28, 2014, after which the "Vermonter" was rerouted to the faster Conn River Line several miles to the west.
Document 7: Long Island Sound: Long Island Sound is a tidal estuary of the Atlantic Ocean, lying between the eastern shores of Bronx County, New York City, southern Westchester County, and Connecticut to the north, and the North Shore of Long Island, to the south. From east to west, the sound stretches 110 miles (177 km) from the East River in New York City, along the North Shore of Long Island, to Block Island Sound. A mix of freshwater from tributaries and saltwater from the ocean, Long Island Sound is 21 miles (34 km) at its widest point and varies in depth from 65 to .
Document 8: Amherst, Massachusetts: Amherst ( ) is a town in Hampshire County, Massachusetts, United States, in the Connecticut River valley. As of the 2010 census, the population was 37,819, making it the largest municipality in Hampshire County (although the county seat is Northampton). The town is home to Amherst College, Hampshire College, and the University of Massachusetts Amherst, three of the Five Colleges. The name of the town is pronounced without the "h" ("AM-erst"), giving rise to the local saying, "only the 'h' is silent", in reference both to the pronunciation and to the town's politically active populace.
Document 9: Hampden County, Massachusetts: Hampden County is a non-governmental county located in the Pioneer Valley of the state of Massachusetts, in the United States. As of the 2010 census, Hampden County's population was 463,490. Its traditional county seat is Springfield, the Connecticut River Valley's largest city, and economic and cultural capital. Hampden County was split from Hampshire County in 1812, because Northampton, Massachusetts, was made Hampshire County's "shire town" in 1794; however, Springfield—theretofore Hampshire County's traditional shire town, dating back to its founding in 1636—grew at a pace far quicker than Northampton and was granted shire town-status over its own, southerly jurisdiction. It was named for John Hampden. To the north of Hampden County is modern-day Hampshire County; to the west is Berkshire County; to the east is Worcester County; to the south are Litchfield County, Hartford County, and Tolland County in Connecticut.
Document 10: East River: The East River is a salt water tidal estuary in New York City. The waterway, which is actually not a river despite its name, connects Upper New York Bay on its south end to Long Island Sound on its north end. It separates the borough of Queens on Long Island from the Bronx on the North American mainland, and also divides Manhattan from Queens and Brooklyn, which is also on Long Island. Because of its connection to Long Island Sound, it was once also known as the "Sound River". The tidal strait changes its direction of flow frequently, and is subject to strong fluctuations in its current, which are accentuated by its narrowness and variety of depths. The waterway is navigable for its entire length of 16 mi , and was historically the center of maritime activities in the city, although that is no longer the case.
Document 11: Mississippi River: The Mississippi River is the chief river of the second-largest drainage system on the North American continent, second only to the Hudson Bay drainage system. Flowing entirely in the United States (although its drainage basin reaches into Canada), it rises in northern Minnesota and meanders slowly southwards for 2320 mi to the Mississippi River Delta at the Gulf of Mexico. With its many tributaries, the Mississippi's watershed drains all or parts of 31 U.S. states and 2 Canadian provinces between the Rocky and Appalachian Mountains. The Mississippi ranks as the fourth-longest and fifteenth-largest river in the world by discharge. The river either borders or passes through the states of Minnesota, Wisconsin, Iowa, Illinois, Missouri, Kentucky, Tennessee, Arkansas, Mississippi, and Louisiana.
Document 12: Hampshire County, Massachusetts: Hampshire County is a historical and judicial county located in the U.S. state of Massachusetts. It has no county government. Instead there is a Hampshire Council of Governments. As of the 2010 census, the population was 158,080. Its most populous municipality is Amherst, and its county seat is Northampton. The county is named after the county Hampshire, in England.
Document 13: Connecticut River Walk Park: The Connecticut River Walk is partially constructed park and bikeway in Springfield, Massachusetts, United States, along the banks of New England's largest river, the Connecticut River. Currently, Springfield's section of this park is 3.7 miles long, running from Chicopee, Massachusetts to the South End Bridge in Springfield, Massachusetts. Unique features of the trail include its path alongside an active - and soon-to-be the United States' first high-speed - train line, making it a "rail-with-trail," and its passing in very close proximity to the Naismith Memorial Basketball Hall of Fame. The longest river in New England, the Connecticut River is the Knowledge Corridor's most prominent natural asset. For centuries it has been a source of regional identity and pride; however, currently most residents are cut off from it by Interstate 91 - a 1960s-era elevated highway, which has become a major inhibitor to Springfield's economic and recreational riverfront growth, especially in recent years.
Document 14: Susquehanna River: The Susquehanna River ( ; Lenape: Siskëwahane) is a major river located in the northeastern United States. At 464 mi long, it is the longest river on the East Coast of the United States that drains into the Atlantic Ocean, via the Chesapeake Bay. With its watershed, it is the 16th-largest river in the United States, and the longest river in the early 21st-century continental United States without commercial boat traffic.
Document 15: Amherst College: Amherst College ( ) is a private liberal arts college located in Amherst, Massachusetts, United States. Founded in 1821 as an attempt to relocate Williams College by its president, Zephaniah Swift Moore, Amherst is the third oldest institution of higher education in Massachusetts. The institution was named after the town, which in turn had been named after Lord Jeffery Amherst. Amherst was established as a men's college and became coeducational in 1975.
ground_truth: New England