Sequani, in ancient geography, were a Gallic people who occupied the upper river basin of the Arar (Saône), the valley of the Doubs and the Jura Mountains, their territory corresponding to Franche-Comté and part of Burgundy.
Sequani is an exonym assigned by the Romans, most likely based on a similar-sounding endonym.
The endonym is not known for certain.
Sequani is like Sequana, Caesar's name for the Seine, but the country of the Sequani is not in the Seine's watershed.
Strabo was originally responsible for the folk-etymologic connection by supposing that the Sequana flowed through the country of the Sequani, a geographic error.
The French name of the Saône, however, the river forming the western border of the Sequani, derives from Celtic Souconna.
The Romans called it the Arar.
William Smith hypothesized that Sequani and Souconna were related.
The country of the Sequani can be defined by the reports of the ancient writers.
The Jura Mountains separated the Sequani from the Helvetii on the east, but the mountains belonged to the Sequani, as the narrow pass between the Rhone and Lake Geneva was Sequanian.
They did not occupy the confluence of the Saône into the Rhone, as the Helvetii plundered the lands of the Aedui there.
Extending a line westward from the Jura estimates the southern border at about Mâcon, but Mâcon belonged to the Aedui.
Strabo says that the Arar separates the Sequani from the Aedui and the Lingones, which means that the Sequani were on the left, or eastern, bank of the Saône only.
On the northeast corner the country of the Sequani touched on the Rhine.Diocletian adds Helvetia, and part of Germania Superior to Sequania, which is now called Provincia Maxima Sequanorum, Vesontio receiving the title of Metropolis civitas Vesontiensium.
