Bernex has an area, as of 2009, of 12.95 square kilometers (5.00 sq mi).
 Of this area, 7.64 km² (2.95 sq mi) or 59.0% is used for agricultural purposes, while 2.14 km² (0.83 sq mi) or 16.5% is forested.
  Of the rest of the land, 2.76 km² (1.07 sq mi) or 21.3% is settled (buildings or roads), 0.41 km² (0.16 sq mi) or 3.2% is either rivers or lakes and 0.02 km² (4.9 acres) or 0.2% is unproductive land.

Of the built up area, housing and buildings made up 10.9% and transportation infrastructure made up 7.3%.
 Power and water infrastructure as well as other special developed areas made up 1.4% of the area while parks, green belts and sports fields made up 1.5%.
 Out of the forested land, 14.9% of the total land area is heavily forested and 1.6% is covered with orchards or small clusters of trees.
 Of the agricultural land, 40.6% is used for growing crops and 5.5% is pastures, while 12.9% is used for orchards or vine crops.
 All the water in the municipality is flowing water.

The municipality is located on the left bank of the Rhone river.
 It consists of 7 villages of Bernex and the hamlets of Chèvres, Loëx, Lully, Cressy, Challoux, Sézenove.
The 7 villages that compose Bernex's municipality are symbolically recalled on the coat of arms by the 7 flames of fire that burn at the top of the hill.
This hill is the culminant point of the municipality (506 m, 1,660 ft), known as the Signal de Bernex, the second highest point of the Geneva canton.
  
The municipality of Bernex consists of the sub-sections or villages of Les Teppes, Châtillon, Chèvres, Loëx, Cressy - Molliers, Saint-Mathieu - Combes, Saint-Mathieu - stand, Luchepelet, Vailly, Le Gamay, La Naz - Guillon.
Bernex has an area, as of 2009, of 12.95 square kilometers (5.00 sq mi).  Of this area, 7.64 km² (2.95 sq mi) or 59.0% is used for agricultural purposes, while 2.14 km² (0.83 sq mi) or 16.5% is forested.   Of the rest of the land, 2.76 km² (1.07 sq mi) or 21.3% is settled (buildings or roads), 0.41 km² (0.16 sq mi) or 3.2% is either rivers or lakes and 0.02 km² (4.9 acres) or 0.2% is unproductive land.
Of the built up area, housing and buildings made up 10.9% and transportation infrastructure made up 7.3%.  Power and water infrastructure as well as other special developed areas made up 1.4% of the area while parks, green belts and sports fields made up 1.5%.  Out of the forested land, 14.9% of the total land area is heavily forested and 1.6% is covered with orchards or small clusters of trees.  Of the agricultural land, 40.6% is used for growing crops and 5.5% is pastures, while 12.9% is used for orchards or vine crops.  All the water in the municipality is flowing water.
The municipality is located on the left bank of the Rhone river.  It consists of 7 villages of Bernex and the hamlets of Chèvres, Loëx, Lully, Cressy, Challoux, Sézenove. The 7 villages that compose Bernex's municipality are symbolically recalled on the coat of arms by the 7 flames of fire that burn at the top of the hill. This hill is the culminant point of the municipality (506 m, 1,660 ft), known as the Signal de Bernex, the second highest point of the Geneva canton.   
The municipality of Bernex consists of the sub-sections or villages of Les Teppes, Châtillon, Chèvres, Loëx, Cressy - Molliers, Saint-Mathieu - Combes, Saint-Mathieu - stand, Luchepelet, Vailly, Le Gamay, La Naz - Guillon.
Bernex, Switzerland