* * *

The "Cobble Hill Tunnel" was built through the hill of the same name at the south end of Brooklyn Heights. Its route was under Atlantic Avenue (then "Street") between Boerum and Court Streets at the eastern end and Columbia and Hicks Streets at the western end. The tunnel was, and is, a 2 track arched roof brick and rubble masoney lined structure built by an unknown contractor.

The corner stone was laid on May 24, 1844 and the tunnel (then only an open cut) was opened on December 3, 1844 and was finished by January 1, 1845. Five years later a "sturdy brick arch" was placed over the cut. As built, the tunnel was 21 feet wide, 17 feet high and 1,611 feet long. There were no stations in the tunnel.

The tunnel was built for the Brooklyn & Jamaica Railroad Company, then a lessee of the Long Island Railroad Company. The LIRR had leased the line to provide a track connection to the East River, as their own tracks then ended at Jamaica. A small railroad station adjoined the "South Ferry" station at the foot of Atlantic Avenue. This was the Brooklyn landing of the ferry that also lent its name to the current location on Manhattan Island from which ferries now embark for Staten Island. The Brooklyn & Jamaica operated small underpowered locomotives which could not negotiate the grades of Cobble Hill without the help of horses. The cut (later tunnel) was built to avoid the use of the noble beasts, and incidentally, to improve the appearance of the then aristocratic neighborhood.

The local residents opposed steam operation from the first and gave the LIRR a very bad time and by 1858 had succeeded in getting a court order to halt steam operation in Brooklyn. The LIRR then decided to abandon their lease of the Brooklyn and Jamaica and to build their own trackage to a different point on the East River. The result was the current LIRR Main Line, built in 1861 from Jamaica to Hunter's Point. The last steam through the tunnel was in 1860, and the last horse pwoered run was on September 30, 1861. The ends of the tunnel were sealed in the fall of 1861.

The Brooklyn & Jamaica eventually became part of the Brooklyn Rapid Transit (BRT) system. In 1875 the LIRR resumed operation on Atlantic Avenue, but going only as far as Flatbush Avenue, under terms of a new agreement with a Brooklyn & Jamaica successor. The LIRR however, never used the Cobble Hill Tunnel after 1861.

Ventilation, and probably light, was supplied by three roof vents at the center of the roof arch which reached the street surface as chimneys on small islands. When the tunnel was sealed, the three roof vents were cut off three feet below the street surface and capped as manholes. These manholes are believed to be the only current access.

The tunnel has been inspected many times since abandonment. It was reportedly used by smugglers after the Civil War. On January 27, 1916. the tunnel was explored and photographed by the Department of Superstructures of the Borough President of Brooklyn's office. It was found to be in relatively good condition, but empty and without rail or ties. In the 1920s the tunnel was reportedly used for both mushroom growing and bootleg whiskey stills. In 1936, New York CIty police broke into the tunnel with jackhammers to look for the body of a hoodlum supposedly buried there.The hoodlum was found later in a barrel of cement in Buffalo. In 1941 the tunnel was again inspected by the federal Works Progress Administration to determine its structural strength. A few years later, it was once again opened, this time by the FBI, in an unsuccessful search for spies. During the late 1950s it was inspected by ERA members George Horn and Martin Schachne, which may have been the last recorded intrusion into the tunnel before Bob Diamond's rediscovery in 1979.