Dialect is one of the language variations spoken by the community in a certain area to interact with each other. Although the use of dialects in a state does exist, the diversity of sub-dialects is still visible in the eyes of most people. The city of Muar, which is located in the state of Johor, is one of the regions that thrives on the existence of various sub-dialects. With the help of the Geographic Information System (GIS) application, this study focuses on identifying the spread of lexical variants of the Malay dialects found in Lenga, Bukit Kepong and Gombang and further describes the spread factors. This study fully uses the field research method involving a total of six study informants and 60 study respondents. The findings of this study show as many as six lexicals with different variant usage while there are nine lexicals that have the same dialect of use in Lenga, Gombang and Bukit Kepong. In addition, this study also shows that there are three factors that spread the variant between these three areas, among them demarcation, landform and space (spatial) and migration. As a result, the implementation of this study proves that the variety of variants in the three areas located in the Muar district brings uniqueness and becomes a heritage and a symbol of pride of the local community. Because the current study serves as a preliminary research on the Muar dialect mapping, the analysis of this study is done at the level of descriptive explanation. Researchers also did not focus on specific lexicons in lexical distribution mapping. Therefore, further studies are suggested to focus on specific lexicons to show the speech variants of the local dialect. Subsequent studies are also recommended not only to focus on lexical distribution mapping but also to present the lexical distribution through the Isogloss Map used.