Portland High School is a public high school established in 1821 in Portland Maine (Cumberland County) which educates grades 912. The school is part of the Portland Public Schools district.Established in 1821 originally as a boys' school Portland High School claims to be the second-oldest public high school still operating in the United States; however it is the 15th oldest public high school in the U.S. Joseph Libbey was its first principal. Given a list of categories: company, educational institution, artist, athlete, office holder, mean of transportation, building, natural place, village, animal, plant, album, film or written work, what category does the paragraph belong to?
A:
Educational Institution