The Oldest Manhole Cover in Brooklyn?
The Brooklyn Water Works was incorporated in 1857 as a private company, which was largely owned by the City of Brooklyn. Brooklyn at that time was acutely aware of the progress that New York City was making in supplying water through the Croton Aqueduct, and wanted to insure an adequate supply for its own growth. The Ridgewood Reservoir was built which collected water from wells and ponds in Nassau County (think Conduit Ave) and then distributed the water to the City. The BWW was succeeded by the Board of Water Supply and Sewerage Commissioners in the 1860's and then by the Department of City Works in 1872. This BWW cover appears then to be --The Oldest Manhole Cover in Brooklyn!
The square grid with raised line design was often used in 19th century covers. Most notable here is the nearly identical use by the Brooklyn Department of City Works (see below).
The BWW was responsible for both water supply and sewer service. The presence of the holes in this cover suggests that it may have been the latter, at least during part of its use.
This cover is at the corner of Ashland Place and Willougby St. on the edge of Fort Greene, Brooklyn. With a second example only a few feet away. In my wanderings they are the last of their kind, although ... there are many streets in Brooklyn.