4 kilometers!
Central Park is a large public park in the middle of Manhattan, in New York City. It is about 4 kilometers (2.5 miles) long, stretching from 59th Street to 110th Street between Fifth Avenue and Central Park West. It covers 843 acres (3.4 square kilometers).
The park is a long rectangle, with city streets on all four sides. New York City's Landmarks Preservation Commission describes it as running about 2.5 miles up the middle of Manhattan. Dividing its area by its length gives an average width of about 850 meters (0.53 miles).
Sources give slightly different areas. The Central Park Conservancy, which cares for the park, gives 843 acres, and NYC Parks, the city's parks department, lists 840.01 acres. The park did not begin at its present size. The land approved for purchase in 1853 ran from 59th Street to 106th Street, and the section north to 110th Street was added in 1859.
In 1853, all the land set aside as green space in Manhattan added up to fewer than 200 acres, and city leaders wanted a great park. In 1858 a design competition drew 33 entries. The winner was the Greensward Plan by Frederick Law Olmsted, a writer and farmer from Connecticut, and Calvert Vaux, a young English architect. It called for broad lawns, woods, streams and lakes.
The roads that cross the park from east to west were sunk well below its surface, so people walking in the park would not notice the traffic. Construction began in 1858, and the Lake opened to the public that same year.
By hand, workers moved nearly 5 million cubic yards (3.8 million cubic meters) of stone, earth and topsoil. They built 36 bridges and arches and planted 500,000 trees, shrubs and vines. The park took about 15 years to build and cost $14 million.
The Central Park Conservancy looks after the park day to day for the City of New York. It counts more than 42 million visits a year, though NYC Parks gives a lower figure of more than 25 million. The park has more than 18,000 trees and is a stopover for more than 200 species of migrating birds. It became a National Historic Landmark in 1963 and a Scenic Landmark of New York City in 1974.