The Flop River is the longest river in Floptropica. It is used as the border between Floptopia, C.V.M, Potaxiene, Floptropica and CupcakKia. It has some cities on its banks however most of it is located in the sparse CupcakKian Hills which is near where the source of the river is. It is approximately 11.14 km in length from the source to the mouth of the river. Many cities are adjacent to the river, such as large cities like Ranpapi City and Floptopia.