New York metropolitan area passed through ports in New York or in one of the surrounding towns. The five boroughs of New York City — The Bronx, Brooklyn, Manhattan, Queens, and Staten Island — were consolidated into a single city in 1898. The newly unified New York City encouraged both more physical connections between the boroughs and the growth of bedroom communities. The New York City Subway began operating in 1904 as the Interborough Rapid Transit Company, one of three systems (the other two being the Brooklyn-Manhattan Transit Corporation and the Independent Subway System) that were later taken over by the city. Railroad stations
Staten Island Tunnel funded by the city, the tunnel was expected to help expand the then-sparsely populated borough in a similar manner to the population and development explosions seen in Brooklyn and the Bronx. Under the Dual Contracts, three routes were proposed—two to Brooklyn and one to Manhattan—which would connect the Staten Island Railway's rapid transit service (SIRT) to existing subway lines. The Manhattan proposal, often called the "direct route," would have connected with the Interborough Rapid Transit Company (IRT)'s lines under Battery Park, near the current Brooklyn–Battery Tunnel. "Direct Route A" would have utilized a five-section tunnel under the New York Harbor,