The original school building on that site, which is now the middle wing of the modern school, was originally divided into two by a brick wall running from top to bottom of the building to divide the girls from the boys.

On February 15, 1919 the new Portland High School along Cumberland Avenue, opened.

[6] The school was added to the National Register of Historic Places on November 23, 1984.

[2] In 1989 a new annex was opened containing more classrooms, a cafeteria, a theater/auditorium (named for John Ford) and an athletic facility.

[7] Portland High School uses the off-campus Fitzpatrick Stadium, Hadlock Field, Portland Expo, and William B. Troubh Ice Arena for the school's sporting events.