<p>This article examines the Batanghari River as an integral component of Southeast Asia’s maritime world by situating it within the framework of the maritime cultural landscape and fluvial maritime systems. Rather than adopting coast-focused interpretations of maritime history, the study argues that inland rivers functioned as active maritime spaces that structured mobility, trade, settlement, and cultural practices across long temporal spans. Using an integrative methodology that combines archaeological evidence with historical sources, the research traces the role of the Batanghari River from the early Srivijaya period through the Malay polities, colonial intervention, and post-independence transformations. Archaeological data, including river-oriented settlement patterns, temple complexes, canal systems, port installations, boat remains, and imported ceramics, demonstrate that the Batanghari River was not merely a transportation corridor. Instead, it functioned as a central organizing axis within an inland maritime system that connected resource-rich interior regions with the Strait of Malacca and wider global trade networks. Historical records further indicate that shifts in political economy, colonial trade monopolies, and infrastructural reconfigurations contributed to the gradual decline of river-based maritime culture and to the displacement of riverine communities. By repositioning the Batanghari River as a core maritime arena rather than a marginal inland space, this study contributes to broader debates in maritime archaeology and Southeast Asian history by highlighting the critical role of rivers in shaping long term maritime connectivity, cultural identity, and socioeconomic transformation.</p>