Madison Square officially opened as a public space in 1847. It occupied land formerly reserved for a potter's field, a military arsenal, and a juvenile reformatory. City planners named the tract after James Madison, the fourth American president, anchoring a rapidly northward-marching street grid. By the 1860s, brownstone mansions lined Madison Avenue, housing elite families like the Jeromes and the Roosevelts.
The transformation into an entertainment hub began when rail operations vacated the area. Cornelius Vanderbilt's New York and Harlem Railroad had maintained its passenger terminal at 26th Street and Madison Avenue. When smoke ordinances forced locomotive traffic north to 42nd Street in 1871, the abandoned shed offered an unusually large footprint within Manhattan's dense grid.
Showman P.T. Barnum leased the open shed in 1874, converted it into his "Great Roman Hippodrome," and hosted chariot races, pageants, and menageries. Bandleader Patrick Gilmore later took over the lease, planting trees, installing fountains, and renaming the hall Gilmore's Garden. Despite these cosmetic efforts, the structure had no roof. Bad weather frequently ruined ticket sales, making long-term operations financially unstable.
