The first high school in Washington, located on Taylor Street, was organized on a three-year basis in 1894 with a typical academic program. In 1906, a four-year high school curriculum was approved. Because of increased enrollment, a new Washington High School facility was built on Carlton Avenue in 1932, with additions constructed in 1951 and 1957. Due to increasing enrollment and the need for instructional facilities that would prepare future graduates for careers in higher education, Washington High School was regionalized into the Warren Hills Regional School District and a new facility was built on Jackson Valley Road. The new facility accommodated students in Grades 10 through 12. The building on Carlton Avenue that formerly housed the high school, was designated as the Warren Hills Regional Junior High School and accommodated students in Grades 6 through 9. Once again, as enrollment increased and outgrew the existing facilities, an addition was constructed to the existing high school in 1989. Upon completion, the enlarged facility on Jackson Valley Road accommodated students from Grades 9 through 12 and the junior high school on Carlton was designated as a middle school, servicing students in Grades 7 and 8.
As the surrounding communities grew, upgrades to the middle school and an addition to the high school were approved by the voters in 2004. The construction authorized in this referendum was completed by June of 2009.
In 2008, the voters of the Warren Hills Regional School District approved a referendum to fund the construction of an athletic facility on Jackson Valley Road across the street from the existing high school. This facility was under construction during the 2009-2010 school year and opened in September of 2010.
The Warren Hills Regional School District services students from Franklin Township, Mansfield Township, Washington Borough and Washington Township. Oxford Township currently sends its high school students to the Warren Hills Regional High School on a tuition basis.