Agafya Lykova, 68, said in her letter a health condition prevented her from preparing enough supplies to endure the harsh winter in the Siberian province of Khakassia, where the average temperature in January is 2 below zero.
Lykova is the last survivor in a family that moved to the area generations ago, RIA Novisti reported.
She is a member of the Old Believers, a religious sect that broke off from the Russian Orthodox church in the 17th century that has faced persecution in the country ever since.
Her location is so remote the next-closest people live about 75 miles away, over extremely rugged terrain.
While officials have known of her presence for some time, her first contact with someone not in her family came when geologists surveying the land encountered them when she was 33.
There is no mail service to the woman's home and it remains unclear how she managed to send the letter to the newspaper. The letter was written in block letters and contained spelling that dates back to before the communist revolution, RIA Novosti said.
Provincial Gov. Aman Tuleyev has traveled to meet Lykova multiple times and pledged he would send a helicopter carrying food and other supplies to the woman's home next week.