Informal cross-border trade plays a significant role in regional integration within ECOWAS (Economic Community of West African States), but its dynamics and impact are not fully understood, especially in Tanzania. A mixed-methods approach combining ethnographic fieldwork with structured interviews and secondary data analysis was employed. Ethnography involved participant observation in border towns, while structured interviews were conducted with traders, local authorities, and community members. Secondary data included trade statistics from ECOWAS and Tanzanian government sources. The study reveals that informal cross-border trade contributes significantly to the economic resilience of border communities, accounting for approximately 20% of total exports in certain regions. Local governance strategies are crucial for managing this trade, with varying levels of success across different jurisdictions. This research highlights the complex interplay between regional integration and local community development through informal cross-border trade. It underscores the need for tailored governance policies that balance economic benefits with social welfare. Policy recommendations include fostering collaboration among border communities, strengthening regulatory frameworks, and enhancing data collection to support evidence-based decision-making in this sector.