Enoshima Island ( 江の島 ) is a scenic destination located adjacent to the cities of Kamakura and Fujisawa.
In real life
Administratively, Enoshima is part of Fujisawa and is connected to its Katase section by way of a 600m (2000ft) bridge. The island sits at the mouth of the Katase River, which flows into Kanagawa Prefecture's Sagami Bay. As the hub of a local resort area, the island is a prime tourist destination. It is now the center of the Shonan ( 湘南 ) resort area that stretches from the town of Oiso to the town of Hayama in the Kanagawa Prefecture. Kamakura, along with Hiratsuka, Chigasaki, and Fujisawa, is also included as part of the Shonan area as well since it rests between Oiso and Hayama.
According to legend, the island was created by the goddess Benzaiten, whose image is seen in both versions of the series, the anime in particular, by way of statues. In 1880, a British merchant named Samuel Cocking purchased much of the island in his Japanese wife's name. After purchasing the land, he built a power plant and botanical gardens on the island, and while the original greenhouse of the gardens was destroyed in the enormous 1923 earthquake in Kanto, the botanical garden itself (now named the Samuel Cocking Garden) still stands and attracts over half a million visitors each year.
Enoshima was the Olympic harbor for the 1964 Summer Olympics, and in 2020, it will be the sailing venue for that year's Summer Olympics.
In Elfen Lied
Enoshima plays a significant part in both the manga and anime versions of Elfen Lied, and some of its prime attractions appear in the story. The famous Enoshima Oohashi Bridge that connects the island to Fujisawa and Kamakura is the battleground for the standoff between Mariko and Nana and eventually Lucy. The famous lighthouse, the Sea Candle, is the final battleground for both manga and anime, as Lucy fights armed forces while trying to save Kouta's life in the former and fights Mariko in the latter.
Though it does not exist in real life, it is conceivable that the island containing the Diclonius Research Institute can be at least sighted from Enoshima, though presumably it is far enough away to suit the Kakuzawas' need for secrecy.
The efforts of Lynn Okamoto in bringing in real life elements of the series' setting mean that Enoshima Island is real to fans in more than one sense of the word.