Why Did New York City Unify in 1898?: When Robert Van Wyck became NYC's 91st Mayor on January 1st, 1898, he suddenly presided over 3 million people and 300 square miles of territory. At the stroke of midnight on that New Year's Day, NYC consolidated into five boroughs. Prior to 1898, NYC merely consisted of Manhattan and parts of the Bronx. But for decades, Manhattan had been looking to grow its influence over surrounding areas like Brooklyn and Long Island City (Queens). In the 1850s, Albany legislators expanded the NYPD's jurisdiction to include Brooklyn. This act marked the first sociopolitical endeavor to unify NYC. Yet as the second half of the 19th century progressed, each decade saw more sociopolitical attempts at consolidation. In the 1860s and 1870s, bridges across the Harlem and East Rivers started to get built primarily because these rivers sometimes froze in the winter, which halted boat traffic and disrupted trade. By the 1880s and 1890s, it was clear that expanding the city's harbor through consolidation would greatly enhance commercial opportunities in the region. And lastly, when Chicago annexed over 100 square miles in 1889, NYC officials feared that many financial and manufacturing firms might move there to take advantage of the "cheap land."