PURPOSE: Ethiopia is highly trachoma endemic. Baseline mapping was needed in Ethiopia's Somali Region to guide elimination efforts. METHODS: Cross-sectional community-based surveys were conducted in 34 suspected trachoma-endemic woredas, grouped as 14 evaluation units (EUs), using a standardised mapping methodology developed for the Global Trachoma Mapping Project. RESULTS: In total, 53,467 individuals were enumerated. A total of 48,058 (89.9%) were present at the time of survey teams' visits and consented to examination. The prevalence of trachomatous inflammation-follicular (TF) among children aged 1-9 years ranged from 4.1% in the EU covering Danot, Boh, and Geladin woredas in Doolo Subzone to 38.1% in the EU covering Kebribeyah and Hareshen woredas in Fafan Subzone (East). The trichiasis prevalence among adults aged over 15 years varied from 0.1% in the EU covering Afder, Bare, and Dolobay woredas in Afder Subzone (West) to 1.2% in the EU covering Awbere in Fafan Subzone (West). CONCLUSION: Mass drug administration (MDA) with azithromycin is needed in 13 EUs (population 2,845,818). Two EUs (population 667,599) had TF prevalences in 1-9-year-olds of ≥30% and will require at least 5 years of MDA; 5 EUs (population 1,1193,032) had TF prevalences of 10-29.9% and need at least three years of MDA; 6 EUs (population 985,187) had TF prevalences of 5-9.9% and need at least one round of azithromycin distribution before re-survey. In all 13 of these EUs, implementation of facial cleanliness and environmental improvement measures is also needed. Surveys are still needed in the remaining 34 unmapped woredas of Somali Region.