Based on the Sounds Comparisons database, this study describes the geographical distribution of the allophony of <u> in 15 words of Mapudungun, using computational techniques associated with Levenshtein measurement, agglomerative clustering, and heat maps. Four contexts of the vowel's occurrence were proposed: bisyllabic words with <u> in the first syllable, bisyllabic words with <u> in the last syllable, bisyllabic words with <u> in both syllables, and monosyllabic words with <u>. Additionally, three observation criteria were considered: the number of vowels in the word, the number of syllables, and the position of the accent. According to the proposed criteria, a high frequency of [(sic)] was observed in almost all contexts, followed by [(sic)], which always appears in the last syllable. The vowel is not geographically related among the localities under study, although there are minimal trends among the macrozones of Northern Araucania, Los Rios, and Argentina, which show some similarity in pronunciation, especially when the vowel is oxytone or monosyllabic. These results were compared to the dialectal distribution proposed by Salas (1978) and Croese (1980), where the allophonic distribution in Sounds Comparisons does not correspond, although there are also minimal trends related to the mentioned macrozones. In more general geographical terms, no significant correlations were found between the pronunciations of the words with <u> and the distances between the localities where they are recorded, suggesting that this vowel does not have an isoglossic behavior or has a more complex distribution than presented in Sounds Comparisons.