The park is made up of 300 acres (1.21 km²) donated by Mary Schenley in 1889 and another 120 acres (0.49 km²) that the city subsequently purchased from her. Another 36 acres (0.15 km²) were acquired at a later date, bringing the park's total size to 456 acres (1.85 km²), and making it the second largest municipal park in Pittsburgh.
Schenley Park features a grand entrance, Schenley Plaza, and several miles of hiking trails and a large lake in Panther Hollow. Across from the Phipps Conservatory & Botanical Gardens is Flagstaff Hill, a popular place to watch outdoor movies in the summer.
In the early days of Schenley Park, the area known as "The Oval" was used for horse racing. Today, it has 13 tennis courts, an all weather running track, and a soccer field. There is also an ice skating rink, public swimming pool, and an 18-hole disc golf course nearby.
In 1842, Mary Elizabeth Croghan of Pittsburgh, who was 15 at the time, eloped with 43-year-old Captain Edward Schenley. The couple moved to England. Mary's father attempted to terminate her inheritance in a lawsuit, but was unsuccessful. Mary's maternal grandfather, General James O'Hara, bequethed to her a parcel of land known as the "Mt. Airy Tract."
Mary's wealth attracted the attention of several land developers in the Pittsburgh area as well as Edward Bigelow, the Director of the Department of Public Works in Pittsburgh. In 1889, Bigelow learned that the agent of a land developer planned to travel to London to attempt to purchase the land from Mary. Bigelow sent an East Liberty lawyer by train to New York City where he then boarded a steamer bound for England. The lawyer beat the real estate agent by two days.
After negotiations with Mary, Bigelow's lawyer entered into an agreement to give 300 acres (1.21 km²) of the Mt. Airy Tract to the city of Pittsburgh with an option to purchase 120 (0.49 km²) more, under the conditions that the park be named after her and never be sold. The city agreed and immediately purchased the additional 120 acres (0.49 km²) of land.
Bigelow began to develop the newly renamed Schenley Park for recreational uses. He hired William Falconer to lead the Phipps Conservatory & Botanical Gardens which was built in 1893. In 1895, Andrew Carnegie built the Carnegie Museum and Music Hall, establishing Oakland and Schenley Park as a cultural icon.