The woman was hiking by herself and was nearly at the summit when she fell, said Lt. Paul Obersteller.
One of the hikers who came to her aid called 911 about 4:50 p.m.
Firefighters and B.C. Ambulance paramedics hiked up the mountain and put the woman in a basket stretcher.
Another crew went up a less-steep part of the mountain in an all-terrain vehicle, which they used to transport the woman.
Firefighters completed the rescue by 8:30 p.m.
Obersteller said the fire department has carried out several rescues in the past few months on Mount Finlayson and reminded hikers to carry cellphones, plenty of water and proper gear.