Varennes-sur-Allier (French pronunciation: [vaʁɛn syʁ alje], literally Varennes on Allier; Occitan: Varenas) is a commune in the Allier department in Auvergne-Rhône-Alpes in central France.

In 52 BC during the Gallic Wars lived by Julius Caesar, Vercingetorix crossed the river Elave (moderne Loire), and started marching up and down the banks of the river Loire, mirroring Caesar's movements and destroying all the bridges to keep him from crossing, the purpose presumably being to destroy part of his force as he attempted to cross.

Realizing Vercingetorix's plan, Caesar resolved to trick him and cross under his very nose.

[3] Caesar one night camped near the town of Varennes,[3] where there had previously been a bridge before Vercingetorix had destroyed it.

[3] Realizing that he had been duped, Vercingetorix set out south, to beat Caesar to Gergovia.