6. The Land Was Acquired With The Prospect Park Purchase
Map of Prospect Park in 1897. The triangular area in the northeast corner would become the botanic garden. Full map of Brooklyn can be found on Wikimedia Commons
June 15, 1864, the city of Brooklyn purchased the land for Prospect Park which also included the land bounded by Eastern Parkway, Empire Boulevard, Flatbush Avenue, and Washington Avenue which would become the Brooklyn Botanic Garden. The land went unused for many years after the acquisition until 1897 when New York State acquired the land for a garden.
In 1909, an agreement between the City of New York and Brooklyn Institute of Arts and Sciences (today, the Brooklyn Museum) created the garden.