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.
Sentence (from "Berwick Academy (Maine)"): 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.
Relevant evidence: No