The research has four purposes, they are: (1) describing the lexical variation of the Malay Language in Sambas Raya; (2) calculating the number of those variations; (3) mapping those variations and (4) creating the lexical isogloss file of the language. The research data were Swadesh and non-Swadesh words and phrases. There are two data analysis methods; quantitative-qualitative descriptive methods and the synchronic comparative method. The method is used to compare the lexical difference between observation points. A dialectometry formulation is used to calculate the lexical difference in the presentation between observation points. There are five results of this research. First, a description of language variation in 9 observation points in Sambas Raya. Second, different lexical numbers, with the lowest number between observation points in point 4 (Sungai Raya) and point 5 (West Singkawang) is 31, and the highest number between observation points in point 2 (Tebas) and point 9 (Seluas) is 69. Third, sub-dialect and different dialects of the language variation. Fourth, the linguistic distance between observation points with the lowest percentage of 31 % in point 4 (Sungai Raya) and point 5 (West Singkawang) and the highest percentage of 69 % in point 2 (Tebas) and point 9 (Seluas). From lexical variation mapping of the language, there are 9 sub-dialect variations, 7 different dialects, and no different language. Fifth, the isogloss line separating the highest language variation with isogloss file separating point 2 (Tebas) and point 9 (Seluas) is 69 files and the lowest language variation with isogloss file separating point 4 (Sungai Raya) and point 5 (West Singkawang) is 31 files.

Index Terms- dialect geography, dialect map, isogloss, lexical variation