Novels with a wilderness setting

One of the first books I remember enjoying as a kid was Hatchet by Gary Paulsen. I grew up out in the country, and spent a lot of time exploring and playing in the woods. Hatchet was the perfect book for a kid my age who was beginning to fall in love with the outdoors.

It occurred to me recently that I really haven't read anything like that as an adult, even though I still have a great love for, and interest in, the outdoors. Are there any novels you can recommend that are set in the wilderness? Specifically, novels with themes of survival and/or exploration?

Thanks in advance for any recommendations!