The island sits on a sharp bend in the river. It is densely covered with tall trees and has a narrow channel behind it. In the nineteenth century there was a thatched cottage on the island linked to the bank by a rustic bridge which was a popular place for picknickers. Alice Liddell used to visit the island with Lewis Carroll, who penned Through the Looking-Glass shortly after one of these visits. There is evidence of weirs and flash locks here, at one time owned by Lord Harcourt, which may account for the name of the island.