This study assesses spatial disparities in the distribution of public facilities across the 22 municipalities of Tissemsilt, an interior province in western Algeria, for the period 2008-2020. Despite national planning efforts, interior regions continue to exhibit pronounced territorial imbalances. The study employs a robust methodological framework coupling Geographic Information Systems (GIS) and Multi-Criteria Analysis (MCA) to evaluate 20 indicators across six essential sectors: education, health, trade, culture, sports, and tourism. A composite Global Index (IG) was constructed to synthesize sectoral performance, and a Spearman Rank Correlation test was applied to statistically validate the systemic nature of these disparities. The results reveal a persistent core-periphery dichotomy, where administrative centers concentrate the majority of services while peripheral and mountainous municipalities remain structurally marginalized. Although 17 out of 22 municipalities showed a relative improvement in their ranking by 2020, the strong correlation (p<0.01) between deicits in health and education confirms that inequalities are deeply structural. Beyond this case study, the proposed GIS-MCA approach offers a replicable diagnostic framework for monitoring Sustainable Development Goals (SDGs) at a micro-regional scale. These findings provide critical insights for policymakers in the Global South to transition from administrative-based allocation toward evidence-based territorial equity.