William Allen High School is one of three, large urban, public high schools of the Allentown School District located in Allentown, Pennsylvania, in the United States. The school provides grades 9th through 12th. William Allen High School is located at 106 North 17th Street, Allentown. It serves students from center-city to the west side of the city. Allentown's other public high school, Dieruff High School, serves students from the city's eastern and southern parts. Until Dieruff's opening in 1959, William Allen High School was known as Allentown High School. In 2015, the school district opened Building 21 Allentown as an experimental high school which focuses on building passion among students through career exploration.