BACKGROUND:
Ethiopia has achieved substantial reductions in under-five mortality. However, national estimates mask subnational disparities, and reliable zonal-level estimates are lacking. Generating precise small-area estimates is essential for identifying high-burden zones and informing local policy action. This study aimed to quantify spatial variation in under-five mortality across Ethiopian zones using household survey data combined with geospatial covariates.

METHODS:
An ecological analysis was conducted using data from the 2019 Mini-Ethiopian Demographic and Health Survey. Under-five mortality risk was estimated at the zonal level through a Bayesian hierarchical spatial small-area estimation (SAE) model. Associations with selected areal-level covariates were assessed. Smoothed relative risks with corresponding 95% credible intervals were reported.

RESULTS:
Marked geographic heterogeneity in under-five mortality was observed. Elevated risks were concentrated in peripheral lowland regions, particularly Somali, Afar, Benishangul-Gumuz, and Gambella. High-burden zones included Afar (zones 1, 2 and 3), Metekel in Benishangul-Gumuz, Anguak and Nuer in Gambella, and Dollo, Faftan, and Liben in Somali. Population density was inversely associated with mortality (RR: 0.83, 95% CrI: 0.77–0.98), while travel time to the nearest city increased the risk of child mortality (RR: 1.24, 95% CrI: 1.02–1.44).

CONCLUSIONS:
Under-five mortality in Ethiopia remains unequally distributed, with persistent hotspots in remote and underserved regions. These disparities reflect structural barriers in health access and infrastructure. Equity-focused strategies addressing geographic accessibility are critical to accelerate progress toward the 2030 Sustainable Development Goal target for child survival.