In May 1888 Stevenson spent about a month in Brielle, New Jersey along the Manasquan River. On the river is a small wooded island, then commonly known as "Osborn Island". One day Stevenson visited the island and was so impressed he whimsically re-christened it "Treasure Island" and carved his initials into a bulkhead. This took place five years after he had completed the novel. To this day, many still refer to the island as such. It is now officially named Nienstedt Island, honoring the family who donated it to the borough.
This island is frequented by river traffic as a place to rest weary arms (after a long paddle), or just a nice place to relax and have a drink. The island itself offers multiple trails crisscrossing the woods, beach areas that allow anyone to come ashore, and a nice relaxing atmosphere.