ten essentials
map, altimeter, compass, GPS device, personal locator beacon
with LED bulb and spare batteries
sunglasses, sun protective clothing, sunscreen
a first aid kit, wrapped in waterproof packaging
hikers on a short trip may also carry a multi-tool, strong adhesive tape and cordage; on a longer trip, further small tools may be useful
the means to both start and sustain a fire; either a butane lighter or matches, or other fire making device. Firestarters for igniting even wet wood, and in areas where no firewood will be available, a stove is highly advisable.
plastic tube tent, jumbo plastic trash bag or bivy sack
at least one day's food for a short hike, that should require no cooking.
drinking water and the skills and tools to purify water
additional items may be needed if spending the night in the emergency shelter