The National Zoological Park, commonly known as the National Zoo, is one of the oldest zoos in the United States. It is part of the Smithsonian Institution and does not charge admission. Founded in 1889, its mission is to “provide engaging experiences with animals and create and share knowledge to save wildlife and habitats. Date opened:May 6, 1889. The Smithsonian’s National Zoo is located in the heart of northwest Washington, D.C. and spans 163 acres.