日本国とアメリカ合衆国との間の相互協力及び安全保障条約
The Treaty of Mutual Cooperation and Security between the United States and Japan, signed in 1960, determined that Washington Heights would remain in operation. The following year, though, the land was deemed necessary for construction of facilities connected with the 1964 Summer Olympics. The transfer was completed in 1964, with the Japanese government bearing the full amount of relocation expenses for U.S. military families moving to Chofu Airport.