Before the merger Sion had an area (as of the September 2004 survey) of . Of this area, about 38.9% is used for agricultural purposes, while 15.5% is forested. Of the rest of the land, 38.4% is settled (buildings or roads) and 7.2% is unproductive land. In the 2004/09 survey a total of or about 17.0% of the total area was covered with buildings, an increase of over the 1980 amount. Over the same time period, the amount of recreational space in the municipality increased by and is now about 4.47% of the total area. Of the agricultural land, is used for orchards and vineyards, is fields and grasslands and consists of alpine grazing areas. Since 1980 the amount of agricultural land has decreased by . Over the same time period the amount of forested land has increased by . Rivers and lakes cover in the municipality.Swiss Federal Statistical Office - Regional portraits accessed 27 October 2016
