The first cornerstone is laid for Fort Hamilton in New York City.
Fort Hamilton is a United States Army installation in the southwestern corner of the New York City borough of Brooklyn, surrounded by the communities of Bay Ridge and Dyker Heights. It is one of several posts that are part of the region which is headquartered by the Military District of Washington. Its mission is to provide the New York metropolitan area with military installation support for the Army National Guard and the United States Army Reserve. The original fort was completed in 1831, with major additions made in the 1870s and 1900s. However, all defenses except about half of the original fort have been demolished or buried.
The cornerstone (or foundation stone or setting stone) is the first stone set in the construction of a masonry foundation. All other stones will be set in reference to this stone, thus determining the position of the entire structure.
Over time a cornerstone became a ceremonial masonry stone, or replica, set in a prominent location on the outside of a building, with an inscription on the stone indicating the construction dates of the building and the names of architect, builder, and other significant individuals. The rite of laying a cornerstone is an important cultural component of eastern architecture and metaphorically in sacred architecture generally.
Some cornerstones include time capsules from, or engravings commemorating, the time a particular building was built.