The largest islands are Inishmore at the northern end of Upper Lough Erne (not to be confused with "Inish More or Davy's Island" in Lower Lough Erne) and Galloon Island at the lower end of Upper Lough Erne. Whether these are entirely bounded by the lake, or partly bounded by the River Erne, is a matter of opinion. The next largest is Boa Island, within Lower Lough Erne. All three of these comprise multiple townlands. Many of the next largest islands constitute a single townland.