Sion is a Swiss town, a municipality, and the capital of the canton of Valais and of the district of Sion. As of December 2019 it had a population of 34,710.
On 17 January 1968, the former municipality of Bramois merged into the municipality of Sion. On 1 January 2013, the former municipality of Salins merged into the municipality of Sion, and on 1 January 2017, Les Agettes did the same.
Landmarks in Sion include the Basilique de Valère and the Château de Tourbillon. Sion has an airfield for civilian and military use, which serves as a base for air rescue missions.