Grand Army Plaza (originally known as The Plaza, or Prospect Park Plaza) was conceived by its designers, Frederick Law Olmsted and Calvert Vaux, simply as a grand entrance to the Park. It was meant as a gateway, to separate the noisy city from the calm nature of the Park. Olmsted and Vaux's design included only a single-spout fountain surrounded by berms (earth embankments) covered in heavy plantings. Instead, though, the 1867 design ended up being much more elaborate and one of the finest formal civic design projects in the United States. The inner ring was originally intended to be a circle, but it actually was arranged as a main street – Flatbush Avenue – with eight connecting radial roads. Instead it consists of concentric rings arranged as streets, with the outer ring being named Plaza Street.
John H. Duncan, designer of Grant's Tomb in Manhattan, designed the Soldiers' and Sailors' Memorial Arch in a classical style similar to the Arc de Triomphe in Paris and patterned after Roan imperial arches. The Civil War memorial arch, the winning entry in a competition, began in 1889. William Tecumseh Sherman laid the cornerstone on October 30, 1889. President Grover Cleveland presided over the unveiling on October 21, 1892.
The Arch gained its monumental statues nine years later. They were first suggested by Stanford White of McKim, Mead and White as part of a plan to formalize the plaza in the spirit of the City Beautiful movement. The Park Commissioner, Frank Squire, liked the ideas, and engaged Frederick MacMonnies in 1894 to design three sculptural groupings for the Arch. The first was installed in 40 separate pieces towering over seven stories above the plaza. Known as the Quadriga, the piece includes the lady Columbia, an allegorical representation of the United States, riding in a chariot accompanied by horses and two winged Victory figures trumpeting her arrival. The other two groupings were installed upon each pedestal of the Arch; the left one was entitled The Spirit of the Army, the right entitled The Spirit of the Navy. Both depict frenzied scenes of soldiers amid unwavering officers charging through the chaos.
A pair of bronze relief panels depicting Abraham Lincoln and Ulysses S. Grant on horseback (the horses were cast by Thomas Eakins and the figures by William O'Donovan) and carved spandrel figures by Philip Martiny were also added.
The Soldiers' and Sailor's Memorial Arch was designated a landmark by the New York Landmarks Preservation Commission in 1973.