In the early 20th century, efforts to preserve natural areas around Chicago led to the creation of the Forest Preserve District of Cook County, established under the Forest Preserve District Act of 1913 and organized the following year after decades of proposals, studies, and legislation. Its first purchase came in 1916 with 500 acres of Deer Grove Forest Preserve in Palatine. In 1919, Edith Rockefeller McCormick donated 83 acres on the condition that the land be used for a modern zoo, and in 1921 the Chicago Zoological Society was chartered as a private nonprofit institution to plan, build, and operate the Chicago Zoological Park, now known as Brookfield Zoo. The partnership between the Chicago Zoological Society and the Forest Preserve District of Cook County, now called the Forest Preserves of Cook County, became a highly regarded public-private conservation partnership in which the Forest Preserves owns the zoo land and buildings and helps fund the zoo while the Society raises most of its operating and capital support. The Society and Brookfield Zoo gained an international reputation for innovation, animal care and welfare, conservation work, education, professional training, and community outreach, while also generating major economic activity, tax revenue, and employment in Illinois.
