Gallia Transalpina was a Roman province located in what is now southeastern France. Established in 121 BC, it was created after the Roman conquest of the region inhabited by the Gauls. The province played a crucial role in the expansion of Roman influence in Gaul and served as a base for further military campaigns. The province was divided into several regions, including Narbonensis, which became a significant cultural and economic center. Gallia Transalpina was known for its prosperous cities, trade routes, and agricultural production, contributing to the wealth of the Roman Empire during its rule.