Tribal gaming establishments play a crucial role in rural economic development, yet their broader impact remains underexplored. This research provides causal evidence that tribal casinos generate positive spillover effects for nearby businesses both on and off reservations. Using mobile device data and casino reopening patterns during COVID-19 as a natural experiment, findings show significant increases in foot traffic to hospitality and retail businesses. These results highlight the importance of economic collaboration between tribal and state governments in resource allocation and revenue planning.