This is a sample list of things you might take on a week-long trip hiking in a wilderness area. Even more than with other kinds of travel, packing for this kind of trip requires compromises between keeping weight down and making sure you bring everything you'll need, because you have to carry it all with you. Depending on where you're going and the time of year, some of the items may not be useful to you, and there are inevitably additional items you'll want to bring along, but this should give you a general idea of what you'll want to pack. (Please keep in mind that we want this list to be useful to people in general, so don't edit it for your own specific needs.) For information and advice about gear selection, see Wilderness backpacking.
2 synthetic undershirts
2 long-sleeve shirts
2 pair of pants (suitable weight for current weather)
2 pair of underwear (long underwear if needed)
2 pair of wool socks
sandals (for wearing when not hiking)
waterproof windbreaker, or at least a jacket.
raingear - ponchos can drape over your pack and save you the expense of a waterproof packcover.
women: 2 good sports bras
oatmeal, cereal bars, trail mix, sausage
gas camping stove
waterproof matches/lighter/fire starter
plate, cup, utensils
dish cloth, scouring sponge
multi-tool pocket knife (e.g. Swiss Army or Leatherman)
plastic bag for trash
water filter -to remove physical debris
iodine tablets -to remove germalogical issues an alternative is water purification tablet
If you're traveling in bear country ensure your food is bagged so it can be tied up and away from the floor.
foam or air mattress
headlamp or flashlight, spare battery
maps, compass - make sure you can read them before you set out.
Stay healthy and safe
after sun treatment such as aloe vera gel
a hat (to shade your face and/or trap heat)
light trekking towel, bioshower-soap
toothbrush, toothpaste, floss
an analgesic painkiller such as aspirin or ibuprofen
blister care (e.g. moleskin, adhesive bandages)
insurance card (Highly unecessary, but doesn't weigh much)
ID card (Highly unecessary, but doesn't weigh much)
cash, bank card (Highly unecessary, but doesn't weigh much)
hankies (dozens of uses, mere ounces of weight)
snakebite kit where appropriate
3 metre length of rope (myriad of potential uses)
women: tampons or pads
a least one lighter, gas or petrol plus small pack of storm matches (can be a life-saver in heavy rain)
topical antiseptic solution (eg Iodine) for cuts, bites and grazes
water proof stuff packs
small shovel (This can be left behind if your pack weight is too heavy already)