姐妹城市是两座城市通过签署官方协议而达成的长期合作伙伴关系，旨在推动文化交流和商务联系。华盛顿目前与14个国家的首都以及美国开国总统乔治·华盛顿 (George Washington)先祖的故乡英国桑德兰签有姐妹城市关系。

The "elder sister", PATYEGARANG, is currently en route to Sydney, Australia. Meanwhile, her "younger sister", BARANGAROO, has made a striking debut in Zhengzhou.