The smallest island in New York City, U Thant Island is located just south of Roosevelt Island in the East River. Measuring only 100 feet wide by 200 feet long, the man-made island was the result of a construction project at the turn of the 20th Century. At that time, William Steinway, a prominent developer in Queens, began plans to build a tunnel under the East River to connect Midtown Manhattan to Astoria. It is the same tunnel that is now in use by the MTA ‘s 7 train. U Thant Island has always been uninhabited, and was mostly overlooked until 1977 when a United Nations organization temporarily leased it in order to revitalize and landscape the site. At that time it became known, unofficially, as U Thant Island, after the former UN Secretary. Unfortunately, access to the island is prohibited to the public, but it can be seen by boat. Gantry Plaza State Park also offers a distant view. Refer to Map for Location.