Druid Hill was opened in 1876 as the first major park purchase by the City under Mayor Thomas Swann (1809-1883), (and later as 33rd Governor of Maryland, 1866-1869) and was later designed by famed nationally-known landscaper Frederick Law Olmsted (1822-1903)[citation needed].

It was later assisted by the organization of a group of supportive friends, animal and wildlife lovers in the Baltimore City Zoological Society, which performed a saving function in the late 1960s when changing demographic and historical populations in the surrounding communities around Druid Hill Park resulted in increased crime and some harassment incidents to the animal population, resulting in a few deaths and maimings, resulted in a protective fence being erected around the zoo campus, and entrance ticketing center and gates which previously had been open to the surrounding Park.

In 1980, when the famous iconic "Harborplace" festival marketplace pavilions at the Inner Harbor by developer James Rouse, opened by downtown Baltimore's waterfront business district and its Patapsco River and Harbor, one of the stalls/stores was of stuffed and children's play fiber animals called "Dr. Watson's Zoo," owned and operated by the now retired Dr. Watson.

[6][7] On August 23, 2022, the Zoo unveiled a ten-year master plan that aims to enhance the visitor experience and include new habitats for the animals.

The plaza features a gift shop, a playground area known as "Celebration Hill", the zoo's original lion statues, and the black-tailed prairie dog exhibit.

Zoo Central features a concessions area, carousel, and children's train ride that traverses the north side of the African Journey exhibit.

The small-model diesel train makes a one-mile circuit and over a 105-foot bridge through parts and scenery of the Zoo, remembering the heritage of the old Baltimore and Ohio Railroad in the city and state, with its long-time decorated colors of blue and gray colors on the locomotive and cars of the old historic road, first railroad built in America since 1827.

The current zoo train from 2010 is pulled by a bright red new detailed scale replica of the 1863-era "C. P. Huntington" locomotive, named for a famous railroading tycoon and magnate in California and Virginia in the 19th and early 20th centuries.

This $20 million project was made to improve living standards for the animals and also to give a much better viewing experience for guests of the zoo.

[18][19] Displaying animals found in Maryland, visitors can watch otters swim over their heads, jump across lily pads, explore a cave, or climb into giant bird nests[citation needed].

It brings guests up-close to nearly 60 (and growing) African black-footed penguins, white-breasted cormorants, and great white pelicans in a vivid re-creation of their natural habitat along the coasts and islands of South Africa.

[29] The Zoo gives guests an extra peek into the lives of the penguins with the opportunity to see them get their daily fill of fish with morning and afternoon feedings.

The Maryland Zoo in Baltimore has been always active in many conservation programs, notably "Polar Bears International," "Project Golden Frog," and their work with African black-footed penguins.