What was the region of ancient Gaul that corresponds to the modern-day Alsace?

The region of ancient Gaul that corresponds to modern-day Alsace is indeed Sequania. Sequania was situated in the eastern part of Gaul and was characterized by the presence of the Jura Mountains and the Saône River, which shaped its geography and settlement patterns. This region was significant in ancient times due to its strategic location and was inhabited by a variety of Celtic tribes.

Although Germania is often associated with the Germanic peoples to the east of the Rhine River, it does not directly correspond to modern Alsace. Similarly, Aquitania, located in the southwest of Gaul, and Alemania, often used to refer to the broader area occupied by Germanic tribes, do not align with the geographic boundaries of Alsace. Therefore, Sequania is recognized as the correct association between ancient Gaul and the region we now know as Alsace.