19th century

New York grew as an economic center, first as a result of Alexander Hamilton's policies and practices as the first Secretary of the Treasury and, later, with the opening of the Erie Canal in 1825, which connected the Atlantic port to the vast agricultural markets of the Midwestern United States and Canada.^[67][68] By 1810 New York City, then confined to Manhattan, had surpassed Philadelphia as the largest city in the United States.^[69]
Tammany Hall, a Democratic Party political machine, began to grow in influence with the support of many of the immigrant Irish, culminating in the election of the first Tammany mayor, Fernando Wood, in 1854. Tammany Hall dominated local politics for decades. Central Park, which opened to the public in 1858, became the first landscaped public park in an American city.^[70][71]
New York City played a complex role in the American Civil War. The city's strong commercial ties to the southern United States, which existed for many reasons, including the industrial power of the Hudson River harbor, which allowed trade with stops such as the West Point Foundry one of the great manufacturing hubs of the early United States, and the city's Atlantic Ocean ports, rendering New York City the American powerhouse in terms of industrial trade between the northern and southern United States. New York's growing immigrant population, which had originated largely from Germany and Ireland, began in the late 1850s to include waves of Italians and Central and Eastern European Jews flowing in en-masse. Anger arose about conscription, with resentment at those who could afford to pay $300 to avoid service leading to resentment against Lincoln's war policies and fomenting paranoia about free Blacks taking the poor immigrants' jobs,^[72] culminating in the three-day-long New York Draft Riots of July 1863. These intense war-time riots are counted among the worst incidents of civil disorder in American history, with an estimated 119 participants and passersby massacred.^[73]
The rate of immigration from Europe grew steeply after the Civil War, and New York became the first stop for millions seeking a new life in the United States, a role acknowledged by the dedication of the Statue of Liberty on October 28, 1886, a gift from the people of France.^[74][75] The new European immigration brought further social upheaval. In a city of tenements packed with poorly paid laborers from dozens of nations, the city was a hotbed of revolution (including anarchists and communists among others), syndicalism, racketeering, and unionization.
In 1883 the opening of the Brooklyn Bridge established a road connection to Brooklyn, across the East River. In 1874 the western portion of the present Bronx County was transferred to New York County from Westchester County, and in 1895 the remainder of the present Bronx County was annexed.^[76] In 1898, when New York City consolidated with three neighboring counties to form "the City of Greater New York", Manhattan and the Bronx, though still one county, were established as two separate boroughs. On January 1, 1914, the New York state legislature created Bronx County, and New York County was reduced to its present boundaries.^[77]

The "Sanitary & Topographical Map of the City and Island of New York", commonly known as the Viele Map, was created by Egbert Ludovicus Viele in 1865