Lower Manhattan, also known as Downtown Manhattan or Downtown New York, is the southernmost part of Manhattan, the central borough of New York City. The neighborhood is the historical birthplace of New York City and for its first 225 years was the entirety of the city. Lower Manhattan serves as the seat of government of both Manhattan and the entire City of New York. Because there are no municipally defined boundaries for the neighborhood, a precise population cannot be quoted, but several sources have suggested that it was one of the fastest-growing locations in New York City between 2010 and 2020, related to the influx of young adults and significant development of new housing units.

Manhattan is the most densely populated and geographically smallest of the five boroughs of New York City. The borough is coextensive with New York County, the smallest county by geographical area in the U.S. state of New York. Located almost entirely on Manhattan Island near the southern tip of the state, Manhattan constitutes the center of the Northeast megalopolis and the urban core of the New York metropolitan area. Manhattan serves as New York City's economic and administrative center and has been described as the cultural, financial, media, and entertainment capital of the world.