Few schools today have a history as rich as Trinity’s.
The history of Trinity can be traced back to the 1850's when Joseph McKnight built Spring Hill as his private residence on the current high school property. In 1867, William W. Smith purchased Spring Hill and later established it as the Trinity Hall Military Academy, an Episcopal boys' school. Trinity Hall became known as one of the best equipped military schools in the United States. There were 34 students enrolled for the first term, but by 1881, the twenty-five room building had to be expanded to accommodate the school's growth. Although Trinity Hall was very successful in preparing young men for Annapolis and West Point, financial failure caused it to close its doors three years after William Smith died in 1904. The property was to remain idle until the 1920's except for the brief period from April 1, 1913 to April 1, 1916 when Company H used the gym building as an armory.
It was not until 1925 that the Trinity Hall Military Academy again became an educational institution. Prior to this, North Franklin and South Strabane Townships had joined to establish a high school on the third floor of the Hood Building (now First National Bank and Trust Company) at the corner of South Main Street and Cherry Avenue. When Amwell and Canton Townships entered this jointure, the four boards purchased Trinity Hall from William W. Smith's son for the sum of one hundred thousand dollars, forty thousand of which was returned to the boards.
The original Trinity Hall Military Academy building, now referred to as Old Main, has served as the focal point for all further expansion. Major structural changes have been made in 1935, 1950, and 1964 and 2006, but Old Main has continued to be Trinity High School's link with the past.
Throughout its history, Trinity High School has kept pace with the community it serves. It has grown from a school of 60 pupils to a student body of approximately 1,300. As the school and community developed, the curriculum shifted from an agricultural emphasis to one that meets the present day needs of a suburban society.
No history of Trinity would be complete without mentioning President Ulysses S. Grant. Grant often visited Trinity Hall as a guest of the Smiths. Four bricks from General Grant's first vault in New York support a marble plaque over the vestibule of Trinity High School today.