Question: This U.S. state's oldest school, Berwick Academy, overlooks the Salmon Falls River which forms part of the state border with New Hampshire. Name the state.

full_context: Document 1: Newichawannock Canal: The Newichawannock Canal is a man-made canal which drains Great East Lake into Horn Pond at the border between Wakefield, New Hampshire, and Acton, Maine, in the northeastern United States. It is at the head of the Salmon Falls River, which the Abenaki called "Newichawannock", meaning "river with many falls". Begun in 1850 by the Great Falls Company to increase the water available for its mills in Somersworth, New Hampshire, the 0.75 mi canal is unusual as it was built for strictly industrial purposes in an area remote from the actual industrial site. The canal forms the boundary between the states of New Hampshire and Maine, and is spanned by a stone bridge built at the same time. The canal and bridge, along with related artifacts, were listed on the National Register of Historic Places in 2014.
Document 2: Wyoming Seminary: Wyoming Seminary, founded in 1844, is a Methodist college preparatory school located in the Wyoming Valley of Northeastern Pennsylvania. The "Lower School," which consists of preschool - 8th grade students, is located in Forty Fort. The "Upper School," comprising 9th-grade to postgraduate students, is located in Kingston. It is near the Susquehanna River and the city of Wilkes-Barre. Locally and in some publications, it is sometimes referred to as "Sem." As a boarding school, only Upper School students are given the opportunity to live (board) on campus. Slightly more than one-third of the Upper School student body reside on campus.
Document 3: Phillips Academy: Phillips Academy Andover (also known as Phillips Academy, Andover, or PA) is a co-educational university-preparatory school for boarding and day students in grades 9–12, along with a post-graduate (PG) year. The school is in Andover, Massachusetts, United States, 25 miles north of Boston. Phillips Academy has 1,150 students, and is a selective school, accepting 13% of applicants. It is part of the Ten Schools Admissions Organization as well as the G20 Schools Group.
Document 4: Big Salmon River (New Brunswick): The Big Salmon River is a small river in southern New Brunswick, Canada, that flows south into the Bay of Fundy. The river has its source to the southwest of Sussex, New Brunswick. The river flows into the Bay of Fundy near St. Martins, New Brunswick, and serves as the endpoint of the Fundy Trail.
Document 5: Bridgton Academy: Bridgton Academy is an all-male college preparatory in North Bridgton, Maine. The school offers a true transitional year, to help students who have completed their senior year of high school gain the academic skills, study skills, self-discipline, and self-confidence necessary to succeed in college. Founded in 1808, the school sits at the northern tip of Long Lake in North Bridgton, Maine. The school has been NEASC accredited since 1934, making it one of the oldest accredited schools in the country. The school is also a member of the National Association of Independent Schools.
Document 6: Horn Pond: Horn Pond is a 227 acre water body located on the border of Acton, Maine, and Wakefield, New Hampshire, in the United States. The lake is both spring-fed and fed by the outflows of Great East Lake to the north and Wilson Lake to the east. Horn Pond's outlet is the Salmon Falls River which forms a natural border between Maine and New Hampshire and empties into the Piscataqua River east of Dover, New Hampshire, and ultimately the Gulf of Maine.
Document 7: Pinkerton Academy: Pinkerton Academy is a secondary school in Derry, New Hampshire, United States. It serves roughly 3,100 students, making it by far the largest high school in New Hampshire, more than 800 students greater than the next largest high school. Pinkerton's situation is unusual, as it is a private school which also serves as the "public" high school (grades 9–12) for the communities of Derry, Hampstead, Chester, Auburn, Candia, and Hooksett. Through arrangements with the towns, each town pays the tuition for their students to attend Pinkerton. For the 2014–15 school year, Hooksett students may attend Pinkerton, following the approval of a short-term enrollment agreement by the Hooksett School Board. Pinkerton Academy is a private, non-profit corporation administered by a headmaster, who in turn acts under the direction of a self-perpetuating board of trustees.
Document 8: Oyster River (New Hampshire): The Oyster River is a 17 mi river in Strafford County, southeastern New Hampshire, United States. It rises in Barrington, flows southeast to Lee, then east-southeast in a serpentine course past Durham to meet the entrance of Great Bay into Little Bay. The bays are tidal inlets of the Atlantic Ocean, to which they are connected by a tidal estuary, the Piscataqua River. The freshwater portion of the river is 14.1 mi long, and the tidal river extends 2.9 mi from Durham to Great Bay.
Document 9: Great East Lake: Great East Lake is an 1825 acre water body located in Carroll County, New Hampshire, and York County, Maine, in the United States. The lake is shared by the towns of Wakefield, New Hampshire, and Acton, Maine, with 45% of its surface area in Acton and 55% in Wakefield. The lake is the farthest upstream of the five headwater lakes of the Salmon Falls River, a tributary of the Piscataqua River. Water from Great East Lake flows out its dam and through the 800 ft Newichawannock Canal into Horn Pond, then into the Salmon Falls River below Horn Pond.
Document 10: Kents Hill School: Kents Hill School (also known as Kents Hill or KHS) is a co-educational independent college-preparatory school for boarding and day students. Kents Hill is located in Kents Hill, Maine, 12 miles west of the state capital of Augusta. It is the 30th oldest boarding school in the United States and one of the oldest continuously operating co-educational college preparatory schools. One of the three oldest Methodist academies in the United States (with Cazenovia and Wilbraham), the school is now a member of the Association of Independent Schools in New England (AISNE) and accredited by the New England Association of Schools and Colleges (NEASC).
Document 11: Bowdoin College: Bowdoin College ( ) is a private liberal arts college located in Brunswick, Maine. At the time Bowdoin was chartered in 1794, Maine was still a part of the Commonwealth of Massachusetts. It offers 33 majors and four additional minors, and offers joint engineering programs with Columbia University, Dartmouth College, and Caltech.
Document 12: Little River (Salmon Falls River): The Little River is a 21.3 mi tributary of the Salmon Falls River in the U.S. state of Maine. It rises from streams in York County, flows southwest through Lebanon, and reaches its confluence with the Salmon Falls River in Berwick.
Document 13: Berwick Academy (Maine): Berwick Academy is a college preparatory school located in South Berwick, Maine. Founded in 1791, it is the oldest educational institution in Maine and one of the oldest private schools in North America. The school sits on a 72-acre, 11-building campus on a hill overlooking the Salmon Falls River, near the border between Maine and New Hampshire. Approximately 565 students in grades Pre-K through 12 (and Post-Grad) attend this coeducational day school, from approximately 60 communities in the surrounding regions of southern Maine, southeastern New Hampshire and northeastern Massachusetts.
Document 14: Salmon Falls River: The Salmon Falls River is a tributary of the Piscataqua River in the U.S. states of Maine and New Hampshire. It rises at Great East Lake, Newichawannock Canal, and Horn Pond and flows south-southeast for approximately 38 mi , forming the border between York County, Maine, and Strafford County, New Hampshire.
Document 15: Lovell Lake: Lovell Lake is a 538 acre water body in Carroll County in eastern New Hampshire, United States, in the town of Wakefield. The lake is both spring-fed and fed by small streams including Horse Brook. The outlet of the lake, located at the village of Sanbornville, is the beginning of the Branch River. From here, the Branch River flows through Milton where it joins the Salmon Falls River on the Maine-New Hampshire border. The Salmon Falls River empties into the tidal waters of the Piscataqua River northwest of Portsmouth, New Hampshire, then into the Gulf of Maine.
ground_truth: Maine