Washington International School (also known as Washington International or simply WIS) is a coeducational international school for day students in grades pre-Kindergarten through 12. The school is located in northwest Washington, DC. Established in 1966, WIS was the first school in the Washington area to offer the International Baccalaureate (IB) program. The school has two campuses: the primary school (grades PK-5) in Georgetown, and the upper school (grades 6-12) in Cleveland Park. The upper school’s campus is located on the grounds of Marjorie Merriweather Post’s Tregaron (estate).