The Saint Louis Zoo, officially known as the Saint Louis Zoological Park, is a zoo in Forest Park, St. Louis, Missouri. It is recognized as a leading zoo in animal management, research, conservation, and education. The zoo is accredited by the Association of Zoos and Aquariums (AZA). Admission is free based on a public subsidy from a cultural tax district, the Metropolitan Zoological Park and Museum District (ZMD); fees are charged for some special attractions. A special feature is the 2 ft narrow-gauge Emerson Zooline Railroad with passenger trains pulled by Chance Rides C.P. Huntington locomotives that encircle the zoo, stopping at the more popular attractions.

Forest Park is a public park in western St. Louis, Missouri. It is a prominent civic center and covers 1,326 acres (5.37 km2). Opened in 1876, more than a decade after its proposal, the park has hosted several significant events, including the Louisiana Purchase Exposition of 1904 and the 1904 Summer Olympics. Bounded by Washington University in St. Louis, Skinker Boulevard, Lindell Boulevard, Kingshighway Boulevard, and Oakland Avenue, it is known as the "Heart of St. Louis" and features a variety of attractions, including the St. Louis Zoo, the St. Louis Art Museum, the Missouri History Museum, and the St. Louis Science Center.