A 1770 map of New York City, including the waterfronts of Brooklyn and New Jersey, turned up at the Brooklyn Historical Society. The Times has the story, with a viewable scan of the restoration.
Given that they’re pushing the visuals, the zoom could be a lot better. But even at this resolution, one can easily make out that the street pattern below Chambers Street remains virtually unchanged after more than 240 years; and that much of the grid of the Lower East Side was already laid out before 1776. Note also the historic route of Fulton Street in Brooklyn, connecting Fulton Ferry (immortalized by Whitman) with today’s east-west Fulton Street via the current north-south route of Cadman Plaza West.
Here’s a Google pinpoint map of the same area, today. Update: here‘s a much higher resolution scan of Ratzer’s depiction of Lower Manhattan and Brooklyn Heights.
Another update: while the article tells us that the map dates to 1770, the legend indicates that the land was actually surveyed in 1766-67, placing its snapshot about a decade before the Declaration of Independence– and in the same year as the first classes at Rutgers.