In 1842 the Croton Reservoir was located between 79th and 86th Streets between Sixth and Seventh Avenues, it was New York City’s new, 31-acre Receiving Reservoir, a body of water built to store fresh drinking water piped in from upstate via the just-completed Croton Aqueduct. Built on high ground on rocky, unpopulated terrain, the reservoir held water that could easily flow down to the southern end of Manhattan, where the city existed at the time. Sloped embankment walls formed its rectangular perimeter. Both the outer and inner walls were covered with stone masonry, with the walls planted on top with grass surrounded by a double fence to create a mile long promenade.
It was finally drained in 1929, after the completion of the new water tunnel. Plans to turn the land into a World War I memorial and then a promenade linking the Metropolitan Museum of Art with the Museum of Natural History were proposed, and then discarded. By 1936, the former reservoir was filled in with land excavated from the development of the Eighth Avenue Subway and Rockefeller Center—and the Great Lawn was born.