Zone A- The area farthest away from the body's center of gravity should be filled with the lightest equipment.
Zone B- This middle area should be packed with medium density objects.
Zone C- This area is the closest to the back and should carry equipment of the greatest density like stoves, tent hardware, water, etc.
HEAVY - HIGHER and LIGHT LOWER
There is also a benefit in placing the densest weight high in the pack as it will be more directly over the center of gravity. A tent should be distributed in Zone C and closer to the top. The sleeping bag can be stuffed in the bottom toward Zone A.