The Helvetii, anglicized as Helvetians, were a Celtic tribe or tribal confederation occupying most of the Swiss plateau at the time of their contact with the Roman Republic in the 1st century BC. According to Julius Caesar, the Helvetians were divided into four subgroups or pagi. Of these, Caesar names only the Verbigeni and the Tigurini, while Posidonius mentions the Tigurini and the Tougeni (Τωυγενοί). They feature prominently in the Commentaries on the Gallic War, with their failed migration attempt to southwestern Gaul serving as a catalyst for Caesar's conquest of Gaul.

The Swiss Plateau or Central Plateau is one of the three major landscapes in Switzerland, lying between the Jura Mountains and the Swiss Alps. It covers about 30% of the Swiss surface area, and is partly flat but mostly hilly. The average height is between 400 metres (1,300 ft) and 700 metres (2,300 ft) AMSL. It is by far the most densely populated region of Switzerland, the center of economy and important transportation.