This paper aims at presenting various kinds of linguistic varieties in Yilan, Taiwan. The linguistic maps showing the current distribution of linguistic varieties that appear as appendices are based on the field survey that the present author conducted from 2005 to 2009 AD as well as the result of recently published field works. They represent the speech of the older generation of I-lan speakers. In addition, this paper attempts to trace the history of linguistic competition and change of linguistic territories for the purpose of furnishing historic explanation of the motivation of linguistic distribution.