The Bronx street grid is irregular. Like the northernmost part of upper Manhattan, the West Bronx's hilly terrain leaves a relatively free-style street grid. Much of the West Bronx's street numbering carries over from upper Manhattan, but does not match it exactly; East 132nd Street is the lowest numbered street in the Bronx. This dates from the mid-19th century when the southwestern area of Westchester County west of the Bronx River, was incorporated into New York City and known as the Northside.
When was the Bronx added to NYC?
the mid-19th century